Leptin actions on the reproductive neuroendocrine axis in sheep

C L Adam, Z A Archer, D W Miller

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

There is a growing literature on the role of leptin in appetite and neuroendocrine regulation in domestic ruminants. Circulating leptin concentration is higher in fat than in thin sheep, is reduced by chronic underfeeding and is higher in sheep subjected to long-day rather than short-day photoperiods. Leptin is reduced acutely by fasting and increases after meals so that there are long- and short-term components to the systemic leptin signal. Nutritional stimulation of reproductive neuroendocrine output is associated with increased circulating concentrations of leptin; peripheral leptin administration restores LH secretion in fasted sheep, and leptin is permissive (although not a trigger) for puberty. Intracerebroventricular (i.c.v.) pharmacological leptin infusion stimulates LH in underfed but not in well-fed sheep, and reduces food intake in well-fed sheep. A single i.c.v. pharmacological injection or physiological infusion of leptin stimulates LH in well-fed sheep, with or without a concomitant decrease in appetite. Furthermore, these appetite and LH responses are differentially affected by photoperiod, indicating that different neuronal pathways may mediate the two responses. Hypothalamic leptin receptors co-localize with orexigenic and anorexigenic neurones, some of which contact GnRH cells, but the confluence of leptin signalling with photoperiod (melatonin) signalling remains unresolved. Photoperiod-entrained sheep provide potential models of altered central leptin sensitivity, in which downstream mechanisms regulating appetite and GnRH may be dissociated.

Original languageEnglish
Pages (from-to)283-297
Number of pages15
JournalReproduction Supplement
Volume61
Publication statusPublished - 2003

Fingerprint

Leptin
Sheep
Photoperiod
Appetite
Gonadotropin-Releasing Hormone
Pharmacology
Appetite Regulation
Leptin Receptors
Ruminants
Melatonin
Puberty
Meals
Fasting
Eating
Fats
Neurons
Injections

Keywords

  • gonadotropin-releasing-hormone
  • amphetamine-regulated-transcript
  • pulsatile luteinizing-hormone
  • hypothalamic gene-expression
  • agouti-related peptide
  • neuropeptide-Y
  • food-intake
  • ovariectomized ewes
  • LH-secretion
  • intracerebroventricular infusion

Cite this

Leptin actions on the reproductive neuroendocrine axis in sheep. / Adam, C L ; Archer, Z A ; Miller, D W .

In: Reproduction Supplement, Vol. 61, 2003, p. 283-297.

Research output: Contribution to journalArticle

Adam, C L ; Archer, Z A ; Miller, D W . / Leptin actions on the reproductive neuroendocrine axis in sheep. In: Reproduction Supplement. 2003 ; Vol. 61. pp. 283-297.
@article{b1995b267f0444428cc6c5f1b56fced8,
title = "Leptin actions on the reproductive neuroendocrine axis in sheep",
abstract = "There is a growing literature on the role of leptin in appetite and neuroendocrine regulation in domestic ruminants. Circulating leptin concentration is higher in fat than in thin sheep, is reduced by chronic underfeeding and is higher in sheep subjected to long-day rather than short-day photoperiods. Leptin is reduced acutely by fasting and increases after meals so that there are long- and short-term components to the systemic leptin signal. Nutritional stimulation of reproductive neuroendocrine output is associated with increased circulating concentrations of leptin; peripheral leptin administration restores LH secretion in fasted sheep, and leptin is permissive (although not a trigger) for puberty. Intracerebroventricular (i.c.v.) pharmacological leptin infusion stimulates LH in underfed but not in well-fed sheep, and reduces food intake in well-fed sheep. A single i.c.v. pharmacological injection or physiological infusion of leptin stimulates LH in well-fed sheep, with or without a concomitant decrease in appetite. Furthermore, these appetite and LH responses are differentially affected by photoperiod, indicating that different neuronal pathways may mediate the two responses. Hypothalamic leptin receptors co-localize with orexigenic and anorexigenic neurones, some of which contact GnRH cells, but the confluence of leptin signalling with photoperiod (melatonin) signalling remains unresolved. Photoperiod-entrained sheep provide potential models of altered central leptin sensitivity, in which downstream mechanisms regulating appetite and GnRH may be dissociated.",
keywords = "gonadotropin-releasing-hormone, amphetamine-regulated-transcript, pulsatile luteinizing-hormone , hypothalamic gene-expression, agouti-related peptide, neuropeptide-Y, food-intake, ovariectomized ewes, LH-secretion, intracerebroventricular infusion",
author = "Adam, {C L} and Archer, {Z A} and Miller, {D W}",
year = "2003",
language = "English",
volume = "61",
pages = "283--297",
journal = "Reproduction Supplement",
issn = "1477-0415",
publisher = "Society for Reproduction and Fertility",

}

TY - JOUR

T1 - Leptin actions on the reproductive neuroendocrine axis in sheep

AU - Adam, C L

AU - Archer, Z A

AU - Miller, D W

PY - 2003

Y1 - 2003

N2 - There is a growing literature on the role of leptin in appetite and neuroendocrine regulation in domestic ruminants. Circulating leptin concentration is higher in fat than in thin sheep, is reduced by chronic underfeeding and is higher in sheep subjected to long-day rather than short-day photoperiods. Leptin is reduced acutely by fasting and increases after meals so that there are long- and short-term components to the systemic leptin signal. Nutritional stimulation of reproductive neuroendocrine output is associated with increased circulating concentrations of leptin; peripheral leptin administration restores LH secretion in fasted sheep, and leptin is permissive (although not a trigger) for puberty. Intracerebroventricular (i.c.v.) pharmacological leptin infusion stimulates LH in underfed but not in well-fed sheep, and reduces food intake in well-fed sheep. A single i.c.v. pharmacological injection or physiological infusion of leptin stimulates LH in well-fed sheep, with or without a concomitant decrease in appetite. Furthermore, these appetite and LH responses are differentially affected by photoperiod, indicating that different neuronal pathways may mediate the two responses. Hypothalamic leptin receptors co-localize with orexigenic and anorexigenic neurones, some of which contact GnRH cells, but the confluence of leptin signalling with photoperiod (melatonin) signalling remains unresolved. Photoperiod-entrained sheep provide potential models of altered central leptin sensitivity, in which downstream mechanisms regulating appetite and GnRH may be dissociated.

AB - There is a growing literature on the role of leptin in appetite and neuroendocrine regulation in domestic ruminants. Circulating leptin concentration is higher in fat than in thin sheep, is reduced by chronic underfeeding and is higher in sheep subjected to long-day rather than short-day photoperiods. Leptin is reduced acutely by fasting and increases after meals so that there are long- and short-term components to the systemic leptin signal. Nutritional stimulation of reproductive neuroendocrine output is associated with increased circulating concentrations of leptin; peripheral leptin administration restores LH secretion in fasted sheep, and leptin is permissive (although not a trigger) for puberty. Intracerebroventricular (i.c.v.) pharmacological leptin infusion stimulates LH in underfed but not in well-fed sheep, and reduces food intake in well-fed sheep. A single i.c.v. pharmacological injection or physiological infusion of leptin stimulates LH in well-fed sheep, with or without a concomitant decrease in appetite. Furthermore, these appetite and LH responses are differentially affected by photoperiod, indicating that different neuronal pathways may mediate the two responses. Hypothalamic leptin receptors co-localize with orexigenic and anorexigenic neurones, some of which contact GnRH cells, but the confluence of leptin signalling with photoperiod (melatonin) signalling remains unresolved. Photoperiod-entrained sheep provide potential models of altered central leptin sensitivity, in which downstream mechanisms regulating appetite and GnRH may be dissociated.

KW - gonadotropin-releasing-hormone

KW - amphetamine-regulated-transcript

KW - pulsatile luteinizing-hormone

KW - hypothalamic gene-expression

KW - agouti-related peptide

KW - neuropeptide-Y

KW - food-intake

KW - ovariectomized ewes

KW - LH-secretion

KW - intracerebroventricular infusion

M3 - Article

VL - 61

SP - 283

EP - 297

JO - Reproduction Supplement

JF - Reproduction Supplement

SN - 1477-0415

ER -