PMID- 14635942
OWN - NLM
STAT- MEDLINE
DCOM- 20031223
LR  - 20061213
IS  - 1477-0415 (Print)
IS  - 1477-0415 (Linking)
VI  - 61
DP  - 2003
TI  - Leptin actions on the reproductive neuroendocrine axis in sheep.
PG  - 283-97
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.
FAU - Adam, C L
AU  - Adam CL
AD  - Molecular Neuroendocrinology Group, Appetite and Energy Balance Division, 
      Aberdeen Centre for Energy Balance and Obesity, Rowett Research Institute, 
      Bucksburn, Aberdeen AB21 9SB, UK. cla@rri.sari.ac.uk
FAU - Archer, Z A
AU  - Archer ZA
FAU - Miller, D W
AU  - Miller DW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Review
PL  - England
TA  - Reprod Suppl
JT  - Reproduction (Cambridge, England). Supplement
JID - 101142074
RN  - 0 (Leptin)
RN  - 33515-09-2 (Gonadotropin-Releasing Hormone)
RN  - 9002-67-9 (Luteinizing Hormone)
SB  - IM
MH  - Animals
MH  - Eating/drug effects
MH  - Female
MH  - Gonadotropin-Releasing Hormone/metabolism
MH  - Hypothalamus/metabolism
MH  - Leptin/*metabolism/pharmacology
MH  - Luteinizing Hormone/metabolism
MH  - Neurosecretory Systems/*physiology
MH  - Reproduction/*physiology
MH  - *Seasons
MH  - Sheep/*physiology
MH  - Signal Transduction/*physiology
RF  - 56
EDAT- 2003/11/26 05:00
MHDA- 2003/12/24 05:00
CRDT- 2003/11/26 05:00
PHST- 2003/11/26 05:00 [pubmed]
PHST- 2003/12/24 05:00 [medline]
PHST- 2003/11/26 05:00 [entrez]
PST - ppublish
SO  - Reprod Suppl. 2003;61:283-97.