Iain Clarke

Summary

Affiliation: Monash University
Country: Australia

Publications

  1. ncbi Control of GnRH secretion: one step back
    Iain J Clarke
    Department of Physiology, Monash University, P O Box 13F, Clayton, Victoria 3800, Australia
    Front Neuroendocrinol 32:367-75. 2011
  2. ncbi Seasonal changes in the expression of neuropeptide Y and pro-opiomelanocortin mRNA in the arcuate nucleus of the ovariectomized ewe: relationship to the seasonal appetite and breeding cycles
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 12:1105-11. 2000
  3. ncbi Targeting energy expenditure in muscle as a means of combating obesity
    Iain J Clarke
    Department of Physiology, Monash University, Melbourne, Victoria, Australia
    Clin Exp Pharmacol Physiol 37:121-4. 2010
  4. ncbi The role of kisspeptin and gonadotropin inhibitory hormone (GnIH) in the seasonality of reproduction in sheep
    I J Clarke
    Dept Physiology, PO Box 13F, Monash University, Clayton, Victoria 3800, Australia
    Soc Reprod Fertil Suppl 67:159-69. 2010
  5. ncbi KiSS-1 messenger ribonucleic acid expression in the hypothalamus of the ewe is regulated by sex steroids and season
    Jeremy T Smith
    Department of Physiology, P O Box 13F, Monash University, Victoria 3800, Australia
    Endocrinology 148:1150-7. 2007
  6. ncbi Two decades of measuring GnRH secretion
    I J Clarke
    Prince Henry s Institute of Medical Research, PO Box 5152, Clayton, Victoria 3168, Australia
    Reprod Suppl 59:1-13. 2002
  7. ncbi Photoperiod effects on gene expression for hypothalamic appetite-regulating peptides and food intake in the ram
    Iain J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria 3168, Australia
    Am J Physiol Regul Integr Comp Physiol 284:R101-15. 2003
  8. ncbi Neonatal immunization against gonadotropin-releasing hormone (GnRH) results in diminished GnRH secretion in adulthood
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Endocrinology 139:2007-14. 1998
  9. ncbi Leptin and the regulation of food intake and the neuroendocrine axis in sheep
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Clin Exp Pharmacol Physiol 28:106-7. 2001
  10. ncbi Multifarious effects of estrogen on the pituitary gonadotrope with special emphasis on studies in the ovine species
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Australia
    Arch Physiol Biochem 110:62-73. 2002

Collaborators

Detail Information

Publications99

  1. ncbi Control of GnRH secretion: one step back
    Iain J Clarke
    Department of Physiology, Monash University, P O Box 13F, Clayton, Victoria 3800, Australia
    Front Neuroendocrinol 32:367-75. 2011
    ..GnIH also modulates the action of GnRH at the level of the pituitary gonadotrope. This review focuses on the role that kisspeptin and GnIH neurons play, as modulators that are 'one step back' from GnRH neurons...
  2. ncbi Seasonal changes in the expression of neuropeptide Y and pro-opiomelanocortin mRNA in the arcuate nucleus of the ovariectomized ewe: relationship to the seasonal appetite and breeding cycles
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 12:1105-11. 2000
    ..Thus, the activity of NPY neurones appears to relate to changes in appetite whereas changes in POMC expression may be relevant to the seasonal breeding cycle...
  3. ncbi Targeting energy expenditure in muscle as a means of combating obesity
    Iain J Clarke
    Department of Physiology, Monash University, Melbourne, Victoria, Australia
    Clin Exp Pharmacol Physiol 37:121-4. 2010
    ..5. We propose that manipulation of skeletal muscle thermogenesis may provide a novel avenue for the development of anti-obesity therapies...
  4. ncbi The role of kisspeptin and gonadotropin inhibitory hormone (GnIH) in the seasonality of reproduction in sheep
    I J Clarke
    Dept Physiology, PO Box 13F, Monash University, Clayton, Victoria 3800, Australia
    Soc Reprod Fertil Suppl 67:159-69. 2010
    ..Reciprocal changes in kisspeptin and GnIH activity explain seasonal changes in the function of GnRH cells...
  5. ncbi KiSS-1 messenger ribonucleic acid expression in the hypothalamus of the ewe is regulated by sex steroids and season
    Jeremy T Smith
    Department of Physiology, P O Box 13F, Monash University, Victoria 3800, Australia
    Endocrinology 148:1150-7. 2007
    ..Furthermore, a seasonal alteration in KiSS-1 expression in the ARC of OVX ewes strongly suggests that kisspeptin is fundamentally involved in the control of seasonal changes in reproductive function...
  6. ncbi Two decades of measuring GnRH secretion
    I J Clarke
    Prince Henry s Institute of Medical Research, PO Box 5152, Clayton, Victoria 3168, Australia
    Reprod Suppl 59:1-13. 2002
    ....
  7. ncbi Photoperiod effects on gene expression for hypothalamic appetite-regulating peptides and food intake in the ram
    Iain J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria 3168, Australia
    Am J Physiol Regul Integr Comp Physiol 284:R101-15. 2003
    ..We conclude that photoperiod-induced increase in VFI correlates with expression of NPY, but not with expression of genes for other putative orexigenic peptides. Ob-Rb gene expression is regulated by photoperiod...
  8. ncbi Neonatal immunization against gonadotropin-releasing hormone (GnRH) results in diminished GnRH secretion in adulthood
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Endocrinology 139:2007-14. 1998
    ..These data indicate that neonatal immunization does not affect the synthesis of GnRH in adulthood but reduces the secretion of GnRH, causing long-term sterility in these animals...
  9. ncbi Leptin and the regulation of food intake and the neuroendocrine axis in sheep
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Clin Exp Pharmacol Physiol 28:106-7. 2001
    ..5. Leptin receptors are found in both the hypothalamus and pituitary and direct action of leptin can be demonstrated on the somatotrophs in the pituitary...
  10. ncbi Multifarious effects of estrogen on the pituitary gonadotrope with special emphasis on studies in the ovine species
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Australia
    Arch Physiol Biochem 110:62-73. 2002
    ....
  11. ncbi Synthesis and secretion of GnRH
    Iain J Clarke
    Prince Henry s Institute of Medical Research, P O Box 5152, Clayton 3168, Australia
    Anim Reprod Sci 88:29-55. 2005
    ..In order to fully understand the central mechanisms that control reproduction, more extensive studies are required on the neuronal circuitry that provides input to GnRH cells...
  12. ncbi Kisspeptin and seasonality in sheep
    Iain J Clarke
    Department of Physiology, Monash University, Victoria 3800, Australia
    Peptides 30:154-63. 2009
    ..The reduction in kisspeptin neuronal function during the non-breeding season can be corrected by infusion of kisspeptin, which causes ovulation in seasonally acyclic females...
  13. ncbi The role of noradrenaline in the generation of the preovulatory LH surge in the ewe
    Iain J Clarke
    Prince Henry s Institute of Medical Research, P O Box 5152, Clayton, VIC 3168, Australia
    Domest Anim Endocrinol 30:260-75. 2006
    ..Thus, increased noradrenergic activity is not a trigger mechanism for initiation of the surge...
  14. ncbi Sex and season are major determinants of voluntary food intake in sheep
    I J Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Reprod Fertil Dev 13:577-82. 2001
    ..In particular, the effect of leptin to reduce food intake is maximal in female sheep in the spring; reasons for the sex difference are discussed...
  15. ncbi Potent action of RFamide-related peptide-3 on pituitary gonadotropes indicative of a hypophysiotropic role in the negative regulation of gonadotropin secretion
    Iain J Clarke
    Department Physiology, Building 13F, Monash University, Clayton Victoria 3800, Australia
    Endocrinology 149:5811-21. 2008
    ..These data indicate that RFRP-3 is a specific and potent mammalian gonadotropin-inhibiting hormone, and that it acts upon pituitary gonadotropes to reduce GnRH-stimulated gonadotropin secretion...
  16. ncbi Models of 'obesity' in large animals and birds
    Iain J Clarke
    Department of Physiology, Monash University, Melbourne, Australia
    Front Horm Res 36:107-17. 2008
    ..This short review highlights particular areas of research in domesticated and wild species that expand our knowledge of systems that are important for our understanding of obesity and metabolism...
  17. ncbi Intensive direct cavernous sinus sampling identifies high-frequency, nearly random patterns of FSH secretion in ovariectomized ewes: combined appraisal by RIA and bioassay
    Iain Clarke
    Prince Henry s Institute of Medical Research, Clayton, Victoria 3168, Australia
    Endocrinology 143:117-29. 2002
    ..We postulate that pattern synchrony of FSH and LH release is effected at the level of the gonadotrope. Concordant FSH and LH pulses probably result from pulsatile GnRH input, but other mechanisms could account for independent FSH pulses...
  18. ncbi Evidence that RF-amide related peptides are inhibitors of reproduction in mammals
    Iain J Clarke
    Department Physiology, Building 13F, Monash University, Clayton VIC 3800, Australia
    Front Neuroendocrinol 30:371-8. 2009
    ..This review will focus on the significant advances in RFRP research in mammalian species...
  19. ncbi Evidence that orexin-containing neurones provide direct input to gonadotropin-releasing hormone neurones in the ovine hypothalamus
    J Iqbal
    Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 13:1033-41. 2001
    ..These findings suggest an integral role for ORX in the regulation of GnRH cells in the sheep and thus provide evidence of a novel mechanism whereby leptin can influence reproductive neuroendocrine function...
  20. ncbi Noradrenergic regulation of hypothalamic cells that produce growth hormone-releasing hormone and somatostatin and the effect of altered adiposity in sheep
    J Iqbal
    Prince Henry's Institute of Medical Research, Clayton, Australia
    J Neuroendocrinol 17:341-52. 2005
    ..Altered activity or noradrenergic neurones in the PBN and LC that occur with reduced body weight may be relevant to the control of GH axis...
  21. ncbi Estradiol-17beta-responsive A1 and A2 noradrenergic cells of the brain stem project to the bed nucleus of the stria terminalis in the ewe brain: a possible route for regulation of gonadotropin releasing hormone cells
    A Pereira
    Department of Physiology, Building 13F, Monash University, Clayton, VIC 3800, Australia
    Neuroscience 165:758-73. 2010
    ..Thus, A1 and A2 noradrenergic neurons project to the BNST in the ewe brain, express ERalpha and are activated by estradiol-17beta. These noradrenergic, estrogen-responsive cells may provide indirect input to GnRH cells, via the BNST...
  22. ncbi Neuropeptide Y (NPY) delays the oestrogen-induced luteinizing hormone (LH) surge in the ovariectomized ewe: further evidence that NPY has a predominant negative effect on LH secretion in the ewe
    K M Estrada
    Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 15:1011-20. 2003
    ....
  23. ncbi Characterization of the projections to the hypothalamic paraventricular and periventricular nuclei in the female sheep brain, using retrograde tracing and immunohistochemistry
    Yue Qi
    Department of Physiology, Monash University, Clayton, Vic, Australia
    Neuroendocrinology 90:31-53. 2009
    ..These studies highlight the differences in the afferent input to these two closely related nuclei in the ovine brain...
  24. ncbi Sex differences in the distribution and abundance of androgen receptor mRNA-containing cells in the preoptic area and hypothalamus of the ram and ewe
    C J Scott
    Department of Physiology, Monash University, Victoria, Australia
    J Neuroendocrinol 16:956-63. 2004
    ..The high level of androgen receptor mRNA expression in the basal hypothalamus, with no sex difference, is consistent with the role of this region in the regulation of gonadotropin secretion...
  25. ncbi Projections of RFamide-related peptide-3 neurones in the ovine hypothalamus, with special reference to regions regulating energy balance and reproduction
    Y Qi
    Department of Physiology, Monash University, Clayton, Victoria, Australia
    J Neuroendocrinol 21:690-7. 2009
    ..We conclude that RFRP-3 neurones project to hypothalamic regions and cells involved in regulation of energy balance and reproduction in the ovine brain...
  26. ncbi Role of sex and sex steroids in mediating pituitary-adrenal responses to acute buspirone treatment in sheep
    J H Broadbear
    Department of Physiology, Monash University, Clayton, Victoria, Australia
    J Neuroendocrinol 17:804-10. 2005
    ....
  27. ncbi Proenkephalin and opioid mu-receptor mRNA expression in ovine hypothalamus across the estrous cycle
    J P Walsh
    Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
    Neuroendocrinology 73:26-36. 2001
    ..This may be part of the neural mechanism underlying the GnRH/LH surge in this species...
  28. ncbi Elevated KiSS-1 expression in the arcuate nucleus prior to the cyclic preovulatory gonadotrophin-releasing hormone/lutenising hormone surge in the ewe suggests a stimulatory role for kisspeptin in oestrogen-positive feedback
    K M Estrada
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 18:806-9. 2006
    ..These data strongly suggest that kisspeptins are involved in the generation of the preovulatory GnRH and luteinising hormone surge...
  29. ncbi The percentage of pituitary gonadotropes with immunoreactive oestradiol receptors increases in the follicular phase of the ovine oestrous cycle
    V A Tobin
    Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 13:846-54. 2001
    ..We suggest that this may be due to increased pulsatile GnRH input rather than rising oestrogen levels...
  30. ncbi Long-term negative feedback effects of oestrogen and progesterone on the pituitary gland of the long-term ovariectomized ewe
    I J Clarke
    Medical Research Centre, Prince Henry s Hospital, Melbourne, Victoria, Australia
    J Endocrinol 120:207-14. 1989
    ..There was no effect of steroidal treatment on pituitary content of LH or pituitary levels of GnRH receptors.(ABSTRACT TRUNCATED AT 250 WORDS)..
  31. ncbi Sex, fat and the tilt of the earth: effects of sex and season on the feeding response to centrally administered leptin in sheep
    I J Clarke
    Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
    Endocrinology 142:2725-8. 2001
    ..These data indicate that responsiveness to leptin depends on sex and also on season in animals that are substantially affected by photoperiod...
  32. ncbi Leptin-mediated effects of undernutrition or fasting on luteinizing hormone and growth hormone secretion in ovariectomized ewes depend on the duration of metabolic perturbation
    B A Henry
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 16:244-55. 2004
    ....
  33. ncbi Immunohistochemical characterization of localization of long-form leptin receptor (OB-Rb) in neurochemically defined cells in the ovine hypothalamus
    J Iqbal
    Prince Henry's Institute of Medical Research, P.O. Box 5152, Victoria 3168, Clayton, Australia
    Brain Res 920:55-64. 2001
    ..Expression of OB-Rb within specific neuropeptidergic neurons provides evidence for the direct action of leptin upon the various neurochemical systems that regulate food intake, neuroendocrine and autonomic function in the brain...
  34. ncbi Stressor specificity of sex differences in hypothalamo-pituitary-adrenal axis activity: cortisol responses to exercise, endotoxin, wetting, and isolation/restraint stress in gonadectomized male and female sheep
    A I Turner
    Department of Physiology, Monash University, Victoria 3800, Australia
    Endocrinology 151:4324-31. 2010
    ....
  35. ncbi Cortisol disrupts the ability of estradiol-17beta to induce the LH surge in ovariectomized ewes
    B N Pierce
    Department of Physiology, Monash University, Victoria, 3800, Australia
    Domest Anim Endocrinol 36:202-8. 2009
    ..These results show that cortisol disrupts the positive feedback effect of E2 to trigger an LH surge and suggest the involvement of multiple mechanisms...
  36. ncbi Isolation and restraint stress results in differential activation of corticotrophin-releasing hormone and arginine vasopressin neurons in sheep
    E T A Rivalland
    Department of Physiology, Building 13 F, Monash University, Monash, Victoria 3800, Australia
    Neuroscience 145:1048-58. 2007
    ..Finally, isolation and restraint stress does not influence co-localization of CRH and AVP in sheep...
  37. ncbi Estradiol enables cortisol to act directly upon the pituitary to suppress pituitary responsiveness to GnRH in sheep
    B N Pierce
    Department of Physiology, Monash University, Vic, Australia
    Neuroendocrinology 89:86-97. 2009
    ....
  38. ncbi Levels of dopamine beta hydroxylase immunoreactivity in the preoptic hypothalamus of the ovariectomised ewe following injection of oestrogen: evidence for increased noradrenaline release around the time of the oestrogen-induced surge in luteinizing hormon
    I J Clarke
    Prince Henry s Institute of Medical Research, PO Box 5152, Clayton, Victoria, Australia
    J Neuroendocrinol 11:503-12. 1999
    ..These data suggest that there is release of noradrenaline in the preoptic area at the time of the E-induced GnRH/LH surge in the OVX ewe...
  39. ncbi Luteinizing hormone-beta mRNA levels are regulated primarily by gonadotropin-releasing hormone and not by negative estrogen feedback on the pituitary
    J E Mercer
    Medical Research Centre, Prince Henry s Hospital, Melbourne, Australia
    Neuroendocrinology 47:563-6. 1988
    ..Long-term regulation of LH-beta mRNA is thus primarily regulated by GnRH...
  40. ncbi Effects of gonadotropin-releasing hormone pulse-frequency modulation on luteinizing hormone, follicle-stimulating hormone and testosterone secretion in hypothalamo/pituitary-disconnected rams
    F C Wu
    Department of Anatomy, Monash University, Melbourne, Australia
    Biol Reprod 37:501-10. 1987
    ....
  41. ncbi Intracerebroventricular infusion of leptin elevates the secretion of luteinising hormone without affecting food intake in long-term food-restricted sheep, but increases growth hormone irrespective of bodyweight
    B A Henry
    Prince Henry's Institute of Medical Research, PO Box 5152 Clayton, Victoria 3168, Australia
    J Endocrinol 168:67-77. 2001
    ..The treatment of leptin was not sufficient to reduce plasma GH levels in the food-restricted animals, suggesting that other factors or mechanisms must be involved in the regulation of this axis...
  42. ncbi Co-localization and distribution of corticotrophin-releasing hormone, arginine vasopressin and enkephalin in the paraventricular nucleus of sheep: a sex comparison
    E T A Rivalland
    Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
    Neuroscience 132:755-66. 2005
    ..We conclude that sex and gonadal status affect peptide distribution in the PVN of the sheep which may provide an anatomical basis for sex differences in HPA axis responses to stress...
  43. ncbi Chronic food-restriction alters the expression of somatostatin and growth hormone-releasing hormone in the ovariectomised ewe
    B A Henry
    Prince Henry's Institute of Medical Research, PO Box 5152 Clayton, Victoria, Australia, 3168
    J Endocrinol 170:R1-5. 2001
    ..In conclusion, the effect of chronic food-restriction on the secretion of GH reflects increased GHRH and reduced SRIF synthesis in the hypothalamus...
  44. ncbi Differential expression of cocaine- and amphetamine-regulated transcript and agouti related-protein in chronically food-restricted sheep
    B A Henry
    Prince Henry's Institute of Medical Research, P.O. Box 5152, Clayton, Vic. 3168, Australia
    Brain Res 918:40-50. 2001
    ..05), but was higher (P<0.01) in the posterior hypothalamic area. Thus, long-term changes in nutritional status have profound effects on the expression of AGRP and CART in the hypothalamus...
  45. ncbi Changes in expression of the genes for the leptin receptor and the growth hormone-releasing peptide/ghrelin receptor in the hypothalamic arcuate nucleus with long-term manipulation of adiposity by dietary means
    Y Kurose
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 17:331-40. 2005
    ..This may be an adaptive mechanism to increase responsivity to both leptin and ghrelin...
  46. ncbi Rapid and specific lowering of pituitary FSH beta mRNA levels by inhibin
    J E Mercer
    Medical Research Centre, Prince Henry s Hospital, Melbourne, Australia
    Mol Cell Endocrinol 53:251-4. 1987
    ..These data show that inhibin has a very rapid and specific effect on FSH beta mRNA levels directly at the level of the pituitary gland...
  47. ncbi Effects of the synthetic glucocorticoid dexamethasone on reproductive function in the ewe
    D J Phillips
    Medical Research Centre, Prince Henry s Hospital Campus, Monash Medical Centre, Melbourne, Australia
    J Endocrinol 126:289-95. 1990
    ..Collectively, these data show that in these experiments dexamethasone did not significantly modify reproductive function in the ewe, a finding that is in contrast to that found in other domestic species...
  48. ncbi Colocalization of kisspeptin and gonadotropin-releasing hormone in the ovine brain
    S Pompolo
    Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
    Endocrinology 147:804-10. 2006
    ..Effects of ovariectomy on the non-GnRH, Kisspeptin-IR cells of the hypothalamus suggest that kisspeptin production is negatively regulated by ovarian steroids...
  49. ncbi Neural connectivity in the mediobasal hypothalamus of the sheep brain
    Y Qi
    Department of Physiology, Monash University, Monash, Australia
    Neuroendocrinology 87:91-112. 2008
    ..These data provide a substrate upon which further understanding of appetite regulation and neuroendocrine function can be derived in this species...
  50. ncbi Psychosocial stress suppresses attractivity, proceptivity and pulsatile LH secretion in the ewe
    B N Pierce
    Department of Physiology, Monash University, Victoria, 3800, Australia
    Horm Behav 54:424-34. 2008
    ....
  51. ncbi Pituitary receptors for gonadotropin-releasing hormone in relation to changes in pituitary and plasma gonadotropins in ovariectomized hypothalamo/pituitary-disconnected ewes. II. A marked rise in receptor number during the acute feedback effects of estrad
    I J Clarke
    Medical Research Centre, Prince Henry s Hospital, Melbourne, Victoria, Australia
    Biol Reprod 39:349-54. 1988
    ..However, the magnitude and direction of the change in receptors number does not account for the changes in pituitary responsiveness to GnRH, suggesting estradiol also modifies post-receptor mechanisms that influence secretion of LH...
  52. ncbi Seasonal differences in the effect of isolation and restraint stress on the luteinizing hormone response to gonadotropin-releasing hormone in hypothalamopituitary disconnected, gonadectomized rams and ewes
    C A Stackpole
    Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
    Biol Reprod 69:1158-64. 2003
    ....
  53. ncbi Perinatal growth and plasma GH profiles in adolescent and adult sheep
    K L Gatford
    Department of Physiology, University of Adelaide, Adelaide, South Australia 5005, Australia
    J Endocrinol 173:151-9. 2002
    ..This suggests that restricted fetal growth and reduced neonatal growth rate in sheep are followed by elevated circulating GH in adolescent and adult males, but GH deficiency or increased GH clearance in adult females...
  54. ncbi Kisspeptin is present in ovine hypophysial portal blood but does not increase during the preovulatory luteinizing hormone surge: evidence that gonadotropes are not direct targets of kisspeptin in vivo
    J T Smith
    Department of Physiology, Monash University, Victoria 3880, Australia
    Endocrinology 149:1951-9. 2008
    ....
  55. ncbi Activation of the hypothalamo-pituitary-adrenal axis by isolation and restraint stress during lactation in ewes: effect of the presence of the lamb and suckling
    A J Tilbrook
    Department of Physiology, P O Box 13 F, Monash University, Clayton 3800, Australia
    Endocrinology 147:3501-9. 2006
    ..We conclude that the activity of the HPA axis during isolation and restraint is reduced in lactating ewes and that the presence of lambs increases this level of attenuation...
  56. ncbi Altered "set-point" of the hypothalamus determines effects of cortisol on food intake, adiposity, and metabolic substrates in sheep
    B A Henry
    Department of Physiology, Building 13 F, Wellington Road, Monash University, VIC 3800, Australia
    Domest Anim Endocrinol 38:46-56. 2010
    ..In sheep, effects of chronically elevated cortisol concentrations on energy balance and metabolism depend upon metabolic setpoint, determined by circannual rhythms...
  57. ncbi Neuroendocrine mechanisms of innate states of attenuated responsiveness of the hypothalamo-pituitary adrenal axis to stress
    A J Tilbrook
    Department of Physiology, Monash University, Victoria, Australia
    Front Neuroendocrinol 27:285-307. 2006
    ..The possible roles of inhibitory central inputs to CRH and AVP neurons and of oxytocin and prolactin in attenuating the HPA axis responses to stress are unknown...
  58. ncbi Kisspeptin neurons in the ovine arcuate nucleus and preoptic area are involved in the preovulatory luteinizing hormone surge
    J T Smith
    Department of Physiology, Monash University, Clayton, Victoria 3880, Australia
    Endocrinology 150:5530-8. 2009
    ..These data suggest kisspeptin neurons located in the caudal extent of the ARC are involved in generating the positive feedback preovulatory GnRH/LH surge in the ewe, but there may also be a role for Kiss1-expressing cells in the POA...
  59. ncbi Pulsatile administration of gonadotrophin-releasing hormone stimulates, in oestrogen-treated anaesthetized ovariectomized ewes, a surge release of LH qualitatively and quantitatively different from that induced by oestradiol in conscious ovariectomized ew
    P J Wright
    Department of Veterinary Clinical Sciences, University of Melbourne, Werribee, Victoria, Australia
    J Endocrinol 116:143-8. 1988
    ....
  60. ncbi Long-term alterations in body weight do not affect the expression of melanocortin receptor-3 and -4 mRNA in the ovine hypothalamus
    J Iqbal
    Prince Henry s Institute of Medical Research, Clayton, VIC 3168, Australia
    Neuroscience 105:931-40. 2001
    ..These findings suggest that long-term alterations in metabolic status do not change the melanocortin receptor mRNA distribution and/or expression in the sheep hypothalamus...
  61. ncbi Seasonal changes in the inputs to gonadotropin-releasing hormone neurones in the ewe brain: an assessment by conventional fluorescence and confocal microscopy
    S Pompolo
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Neuroendocrinol 15:538-45. 2003
    ....
  62. ncbi Negative feedback regulation of the secretion and actions of gonadotropin-releasing hormone in males
    A J Tilbrook
    Department of Physiology, Monash University, Victoria 3800, Australia Prince Henry s Institute of Medical Research, Clayton, Victoria 3168, Australia
    Biol Reprod 64:735-42. 2001
    ..The mechanisms of action for inhibin are not known...
  63. ncbi Influence of the degree of stimulation of the pituitary by gonadotropin-releasing hormone on the action of inhibin and testosterone to suppress the secretion of the gonadotropins in rams
    A J Tilbrook
    Department of Physiology, P O Box 13F, Monash University, Victoria, 3800, Australia
    Biol Reprod 64:473-81. 2001
    ..Inhibin may be capable of suppressing LH secretion under conditions of low GnRH...
  64. ncbi Diverse intracellular signalling systems used by growth hormone-releasing hormone in regulating voltage-gated Ca2+ or K channels in pituitary somatotropes
    C Chen
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Immunol Cell Biol 78:356-68. 2000
    ..The GHRH-induced alteration of Ca2+ and K+ currents augments the influx of Ca2+, leading to an increase in [Ca2+]i and the GH secretion...
  65. ncbi The distribution of cells containing estrogen receptor-alpha (ERalpha) and ERbeta messenger ribonucleic acid in the preoptic area and hypothalamus of the sheep: comparison of males and females
    C J Scott
    Department of Physiology, Monash University and Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Endocrinology 141:2951-62. 2000
    ..Low levels of ERbeta mRNA in the preoptic area and ventromedial and arcuate nuclei, regions known to be important for the regulation of reproduction, suggest that ERbeta may not be involved in these functions...
  66. ncbi The distribution of progesterone receptor immunoreactivity and mRNA in the preoptic area and hypothalamus of the ewe: upregulation of progesterone receptor mRNA in the mediobasal hypothalamus by oestrogen
    C J Scott
    Department of Physiology, Monash University, Clayton, Victoria, Australia
    J Neuroendocrinol 12:565-75. 2000
    ..Oestrogen and progesterone synergize to inhibit GnRH secretion and the present results suggest that these functions may involve cells of the VMN and ARC, with oestrogen acting to upregulate PR...
  67. ncbi Gonadal steroid receptors in the regulation of GnRH secretion in farm animals
    C J Scott
    Department of Physiology, Monash University, VIC 3168, Clayton, Australia
    Anim Reprod Sci 60:313-26. 2000
    ..The receptor mapping, neuronal tracing and microimplantation studies suggest that the ventromedial nucleus is likely to be a key hypothalamic nucleus in the steroid regulation of GnRH secretion in sheep...
  68. ncbi Stress and reproduction: central mechanisms and sex differences in non-rodent species
    A J Tilbrook
    Department of Physiology, P O Box 13F, Monash University, 3800, Victoria, Australia
    Stress 5:83-100. 2002
    ..Furthermore, there is a need to know how stress influences the feedback actions of gonadal steroids and inhibin...
  69. ncbi Growth hormone-releasing peptide-2 (GHRP-2) does not act via the human growth hormone-releasing factor receptor in GC cells
    C Chen
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Endocrine 9:71-7. 1998
    ..Incubation of the transfected cells with 10(-1)-10(-8)MGH RP-2 did not modify intracellular cAMP levels. This result suggests that GHRP-2 does not act through the GRF receptor...
  70. ncbi Oestrogen receptors in the brainstem of the female sheep: relationship to noradrenergic cells and cells projecting to the medial preoptic area
    C J Scott
    Department of Physiology, Monash University, Clayton, Vic, Australia
    J Neuroendocrinol 11:745-55. 1999
    ..The cells of the caudal ventrolateral medulla which contain ER-ir cells that project to the preoptic area may be important in the mediation by noradrenaline of the actions of oestrogen on GnRH secretion in the ewe...
  71. ncbi Angiotensin II- and phorbol ester-induced steroidogenesis by ovine adrenocortical cells: effect of sex and the gonadal status of the donor animal
    B J Canny
    Department of Physiology, Monash University, Clayton, Victoria, Australia
    Clin Exp Pharmacol Physiol 25:401-4. 1998
    ..In addition, sex and gonadal factors may play an important role in regulating the responsiveness of adrenocortical cells to these factors...
  72. ncbi The effects of GH-releasing peptide-6 (GHRP-6) and GHRP-2 on intracellular adenosine 3',5'-monophosphate (cAMP) levels and GH secretion in ovine and rat somatotrophs
    D Wu
    Prince Henry s Institute of Medical Research, Victoria, Australia
    J Endocrinol 148:197-205. 1996
    ..These data indicate species differences in the response of pituitary somatotrophs to the GHRPs and this is probably due to different subtypes of GHRP receptor in rat or sheep...
  73. ncbi The effect of GH-releasing peptide-2 (GHRP-2 or KP 102) on GH secretion from primary cultured ovine pituitary cells can be abolished by a specific GH-releasing factor (GRF) receptor antagonist
    D Wu
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    J Endocrinol 140:R9-13. 1994
    ..GH release in response to KP 102 involves an increase in Ca2+ influx and there is no cross-desensitization between KP 102 and GRF responses...
  74. ncbi Gonadotrophin-releasing hormone secretion (GnRH) in anoestrous ewes and the induction of GnRH surges by oestrogen
    I J Clarke
    Medical Research Centre, Prince Henry s Hospital, Melbourne, Australia
    J Endocrinol 117:355-60. 1988
    ....
  75. ncbi Hypophyseal-portal somatostatin (SRIH) and jugular venous growth hormone secretion in the conscious unrestrained ewe
    Johannes D Veldhuis
    Division of Endocrinology and Metabolism, Department of Internal Medicine, Center for Biomathematical Technology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
    Neuroendocrinology 75:83-91. 2002
    ..We conclude that, to the extent that in vivo sampling reflects physiological SRIH/somatotrope activity, the female sheep maintains complex time-varying interactions between SRIH and GH release...
  76. ncbi Responses of the hypothalamopituitary adrenal axis and the sympathoadrenal system to isolation/restraint stress in sheep of different adiposity
    Alan J Tilbrook
    Department of Physiology, Monash University, Monash, Vic, Australia
    Neuroendocrinology 87:193-205. 2008
    ....
  77. ncbi The effect of testosterone and season on prodynorphin messenger RNA expression in the preoptic area-hypothalamus of the ram
    Christopher J Scott
    Department of Physiology, Monash University, Vic, Australia School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
    Domest Anim Endocrinol 34:440-50. 2008
    ..We conclude that testosterone and season regulate prodynorphin mRNA expression in a region-specific manner, which may influence seasonal changes in reproductive function...
  78. ncbi Selective regulation of glutamic decarboxylase isoform 65, but not isoform 67, in the bed nucleus of the stria terminalis and the preoptic area of the ewe brain across the estrous cycle
    Sueli Pompolo
    Prince Henry s Institute of Medical Research, Clayton, Victoria 3168, Australia
    Endocrinology 143:544-50. 2002
    ..GAD(65) is thought to be the active enzyme during periods of high demand of GABA and our results are consistent with the GABA neurons of BnST being most active during the luteal phase of the estrous cycle...
  79. ncbi Does the type II glucocorticoid receptor mediate cortisol-induced suppression in pituitary responsiveness to gonadotropin-releasing hormone?
    Kellie M Breen
    Reproductive Sciences Program, University of Michigan, 300 North Ingalls Building, Room 1101 SW, Ann Arbor, Michigan 48109-0404, USA
    Endocrinology 145:2739-46. 2004
    ..Together, these observations imply that the type II GR mediates cortisol-induced suppression of pituitary responsiveness to GnRH...
  80. ncbi Y2 receptor-selective agonist delays the estrogen-induced luteinizing hormone surge in ovariectomized ewes, but y1-receptor-selective agonist stimulates voluntary food intake
    Iain J Clarke
    Prince Henry s Institute of Medical Research, P O Box 5152, Clayton, Victoria 3168, Australia
    Endocrinology 146:769-75. 2005
    ..We conclude that, in sheep, the negative regulation of the reproductive axis by NPY and Y-receptor agonists is effected via the Y2 receptors, whereas the orexigenic effects are most likely effected via the Y1 receptors...
  81. ncbi Profiling postprandial thermogenesis in muscle and fat of sheep and the central effect of leptin administration
    Belinda A Henry
    Department of Physiology, Monash University, Wellington Road, Victoria 3800, Australia
    Endocrinology 149:2019-26. 2008
    ..These data demonstrate that leptin is able to regulate thermogenesis in muscle, providing a novel target for the manipulation of energy balance...
  82. ncbi Noradrenaline, but not neuropeptide Y, is elevated in cerebrospinal fluid from the third cerebral ventricle following audiovisual stress in gonadectomised rams and ewes
    Anne I Turner
    Department of Physiology, Monash University, Australia
    Neuroendocrinology 76:373-80. 2002
    ..We conclude that the sex differences in the stress-induced activity of the hypothalamo-pituitary-adrenal axis in sheep are not likely to be due to differences in the level of noradrenergic and/or NPY input to the hypothalamus...
  83. ncbi Reduction in adiposity affects the extent of afferent projections to growth hormone-releasing hormone and somatostatin neurons and the degree of colocalization of neuropeptides in growth hormone-releasing hormone and somatostatin cells of the ovine hypoth
    Javed Iqbal
    Prince Henry's Institute of Medical Research, Victoria, Australia
    Endocrinology 146:4776-85. 2005
    ..Increased input to SRIF cells in lean animals may be inhibitory and permissive of increased GH. The appearance of NPY in GHRH cells of lean animals may be a mechanism for regulation of increasing GH secretion with reduced adiposity...
  84. ncbi Effects of changing gonadotropin-releasing hormone pulse frequency and estrogen treatment on levels of estradiol receptor-alpha and induction of Fos and phosphorylated cyclic adenosine monophosphate response element binding protein in pituitary gonadotrop
    Iain J Clarke
    Prince Henry s Institute of Medical Research, P O Box 5152, Clayton, Victoria 3168, Australia
    Endocrinology 146:1128-37. 2005
    ..This suggests convergence of signaling for GnRH and estrogen...
  85. ncbi Activin A: from sometime reproductive factor to genuine cytokine
    David J Phillips
    Monash Institute of Medical Research, Monash University, 27 31 Wright Street, Clayton, VIC 3168, Australia
    Vet Immunol Immunopathol 108:23-7. 2005
    ..Activin A therefore seems to be part of the regulatory component of the innate immune response...
  86. ncbi Effects of central infusion of ghrelin on food intake and plasma levels of growth hormone, luteinizing hormone, prolactin, and cortisol secretion in sheep
    Javed Iqbal
    Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
    Endocrinology 147:510-9. 2006
    ..Thus, ghrelin does not appear to be a significant regulator of ingestive behavior in this species of ruminant but acts centrally to indirectly regulate GH and LH secretion...
  87. ncbi Progesterone-receptive dopaminergic and neuropeptide Y neurons project from the arcuate nucleus to gonadotropin-releasing hormone-rich regions of the ovine preoptic area
    Laurence Dufourny
    Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
    Neuroendocrinology 82:21-31. 2005
    ..This study suggests that subsets of arcuate nucleus dopaminergic and NPY neurons may transduce, at least in part, the progesterone-mediated inhibition of GnRH secretion...
  88. ncbi Antidepressants, sex steroids and pituitary-adrenal response in sheep
    Jillian H Broadbear
    Department of Physiology, Building 13F, Monash University, Clayton, Vic, 3800, Australia
    Psychopharmacology (Berl) 175:247-55. 2004
    ..This highlights the potential significance of sex and circulating sex steroids in modulating neuroendocrine responses to antidepressants, and may have an impact on our understanding of the actions of these drugs in men and women...
  89. ncbi Influence of photoperiod and gonadal status on food intake, adiposity, and gene expression of hypothalamic appetite regulators in a seasonal mammal
    Chantacha Anukulkitch
    Prince Henry s Institute of Medical Research, Clayton, Victoria, Australia
    Am J Physiol Regul Integr Comp Physiol 292:R242-52. 2007
    ....
  90. ncbi Sex differences in the pituitary-adrenal response following acute antidepressant treatment in sheep
    Jillian H Broadbear
    Department of Physiology, Monash University, 3800, Victoria, Australia
    Psychopharmacology (Berl) 171:450-7. 2004
    ..CONCLUSIONS: These data suggest that the HPA axes of females are more sensitive to the stimulatory effects of serotonin following acute treatment with the SSRI, sertraline...
  91. ncbi Sex difference in the suppressive effect of cortisol on pulsatile secretion of luteinizing hormone in sheep
    Catherine A Stackpole
    Department of Physiology, P.O. Box 13F, Monash University, Victoria 3800, Australia
    Endocrinology 147:5921-31. 2006
    ..The results of experiment 2 suggest that intact hypothalamic input to the pituitary is necessary for cortisol to inhibit pituitary responsiveness to GnRH...
  92. ncbi Effect of testosterone and season on proenkephalin messenger RNA expression in the preoptic area of the hypothalamus in the ram
    Christopher J Scott
    Department of Physiology, Monash University, Victoria, Australia
    Biol Reprod 69:2015-21. 2003
    ..No differences were observed between treatments in seven other regions examined. We conclude that testosterone and season regulate proenkephalin mRNA levels in the preoptic area/hypothalamus in the ram in a region-specific manner...
  93. ncbi Projections to the preoptic area from the paraventricular nucleus, arcuate nucleus and the bed nucleus of the stria terminalis are unlikely to be involved in stress-induced suppression of GnRH secretion in sheep
    Elizabeth T A Rivalland
    Department of Physiology, Monash University, Melbourne, Vic, Australia
    Neuroendocrinology 84:1-13. 2006
    ..If cells of these regions are involved in GnRH suppression during stress, this may occur via interneuronal pathways...
  94. ncbi Characterizing a mammalian circannual pacemaker
    Gerald A Lincoln
    Centre for Reproductive Biology, University of Edinburgh, Queen s Medical Research Institute, Edinburgh, Scotland
    Science 314:1941-4. 2006
    ..These new insights open the way for a molecular analysis of long-term timing mechanisms...
  95. ncbi Neuronal inputs from the hypothalamus and brain stem to the medial preoptic area of the ram: neurochemical correlates and comparison to the ewe
    Christopher J Scott
    Department of Physiology, Monash University, Victoria 3800, Australia
    Biol Reprod 68:1119-33. 2003
    ..Although dopamine, beta-endorphin, and neuropeptide Y have been implicated in the regulation of GnRH secretion in males, it is unlikely that these neurotransmitters regulate GnRH secretion via direct inputs to GnRH neurons...
  96. ncbi Rapid in vivo effects of estradiol-17beta in ovine pituitary gonadotropes are displayed by phosphorylation of extracellularly regulated kinase, serine/threonine kinase, and 3',5'-cyclic adenosine 5'-monophosphate-responsive element-binding protein
    Javed Iqbal
    Department of Physiology, Monash University, Clayton, Victoria 3880, Australia
    Endocrinology 148:5794-802. 2007
    ..Thus, rapid effects of E17beta on gonadotropes involve phosphorylation of second messenger proteins with a time course that may relate to the rapid negative feedback effect to reduce responsiveness to GnRH...
  97. ncbi Kisspeptin neurons in the arcuate nucleus of the ewe express both dynorphin A and neurokinin B
    Robert L Goodman
    Department of Physiology and Pharmacology, West Virginia University, Morgantown, West Virginia, USA
    Endocrinology 148:5752-60. 2007
    ..Because virtually all of these neurons express estrogen and progesterone re-ceptors, they are likely to relay the feedback effects of these steroids to GnRH neurons to regulate reproductive function...
  98. ncbi Redefining the limits of day length responsiveness in a seasonal mammal
    Gabriela C Wagner
    School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, United Kingdom
    Endocrinology 149:32-9. 2008
    ..This adaptive mechanism may be related to the latitude of origin and the timing of the seasonal transitions...
  99. ncbi Progesterone-receptive beta-endorphin and dynorphin B neurons in the arcuate nucleus project to regions of high gonadotropin-releasing hormone neuron density in the ovine preoptic area
    Laurence Dufourny
    Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
    Neuroendocrinology 81:139-49. 2005
    ..These data strongly support the hypothesis that progesterone acts in the arcuate nucleus through beta-endorphin and dynorphin B neurons to affect preoptic area GnRH neurons...