The stimulatory effect of leptin on the neuroendocrine reproductive axis of the monkey

• Published in: Endocrinology (Philadelphia) Vol. 139; no. 11; pp. 4652 - 4662
• Main Authors: Finn, P D, Cunningham, M J, Pau, K Y, Spies, H G, Clifton, D K, Steiner, R A
• Format: Journal Article
• Language: English
• Published: United States 01-11-1998
• Subjects: Animals; Brain Chemistry - drug effects; Follicle Stimulating Hormone - biosynthesis; Gonadotropin-Releasing Hormone - biosynthesis; Hormones - biosynthesis; Hormones - blood; In Situ Hybridization; Leptin; Luteinizing Hormone - biosynthesis; Macaca mulatta; Male; Neurosecretory Systems - drug effects; Pro-Opiomelanocortin - biosynthesis; Proteins - pharmacology; Reproduction - drug effects; RNA Probes; RNA, Messenger - biosynthesis; Stimulation, Chemical
• ISSN: 0013-7227
• DOI: 10.1210/en.139.11.4652

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.