title: Nitric oxide mediates leptin-induced preovulatory luteinizing hormone and prolactin surges in rats.
abstract: The objective of this study was to investigate whether nitric oxide (NO) plays a significant role in mediating the facilitatory action of leptin on the reproductive system. The covariate of reproductive function we used for evaluation was preovulatory surges of luteinizing hormone (LH) and prolactin (PRL), which were simulated by priming ovariectomized rats with estradiol and progesterone. A systemic treatment of normally-fed rats with an NO synthase inhibitor (N(W)-nitro-L-arginine methyl ester) significantly decreased the magnitude of both LH and PRL surges. Three-day-fasted rats did not show a significant surge of either LH or PRL. An intracerebroventricular administration of leptin to fasted rats led to a significant recovery of these hormonal surges, but a simultaneous administration of both the NO synthase inhibitor and leptin significantly abrogated the effects of leptin. This is the first report to demonstrate a significant intermediary role of NO in leptin-induced preovulatory LH and PRL surges in rats.
authors.affiliation: Division of Internal Medicine, Clinical Research Center, International University of Health and Welfare, 2600-1 Kitakanemaru, Otawara, Tochigi 324-8501, Japan. watah@iuhw.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Watanobe
authors.forename: H B
authors.initials: HB
authors.lastname: Schiöth
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005498:Follicular Phase / Q000187:drug effects / Q000502:physiology*; D007276:Injections, Intraventricular; D020738:Leptin / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010052:Ovariectomy; D011374:Progesterone / Q000494:pharmacology; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004791:Enzyme Inhibitors; D020738:Leptin; D009569:Nitric Oxide; D011374:Progesterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester