The stimulatory effect of leptin on the neuroendocrine reproductive axis of the monkey.
Leptin acts as a metabolic activator of the neuroendocrine reproductive axis in several rodent species, but whether leptin plays a similar role in primates is unknown. To explore this question, we examined the effects of leptin on gonadotropin and testosterone secretion in male rhesus monkeys that were fasted for 2 days. Mean plasma levels of LH and FSH, LH pulse frequency, and LH pulse amplitude were significantly higher in leptin-treated animals compared with saline-treated controls during the second day of the fast. To identify targets for leptin's action, we used in situ hybridization and computerized imaging to map leptin receptor (Ob-R) messenger RNA (mRNA) distribution. Ob-R mRNA was observed in the anterior pituitary and several areas of the brain, including the arcuate and ventromedial nuclei of the hypothalamus. Ob-R mRNA was coexpressed in both POMC and neuropeptide Y neurons in the arcuate nucleus, whereas little or no coexpression of Ob-R mRNA was evident in GnRH neurons. These results suggest that leptin is a metabolic signal to the reproductive axis in primates and imply that both POMC and neuropeptide Y neurons are involved in mediating leptin's effects in the brain.
Finn
P D
PD
Department of Physiology and Biophysics, University of Washington, Seattle 98195, USA.
Cunningham
M J
MJ
Pau
K Y
KY
Spies
H G
HG
Clifton
D K
DK
Steiner
R A
RA
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D005640:Follicle Stimulating Hormone / Q000096:biosynthesis; D007987:Gonadotropin-Releasing Hormone / Q000096:biosynthesis; D006728:Hormones / Q000096:biosynthesis / Q000097:blood; D017403:In Situ Hybridization; D020738:Leptin; D007986:Luteinizing Hormone / Q000096:biosynthesis; D008253:Macaca mulatta; D008297:Male; D009490:Neurosecretory Systems / Q000187:drug effects*; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis; D011506:Proteins / Q000494:pharmacology*; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis; D012098:Reproduction / Q000187:drug effects*; D013268:Stimulation, Chemical
D006728:Hormones; D020738:Leptin; D011506:Proteins; D015347:RNA Probes; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D011333:Pro-Opiomelanocortin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone