A significant participation of orexin-A, a potent orexigenic peptide, in the preovulatory luteinizing hormone and prolactin surges in the rat.
Orexins are novel hypothalamic peptides which stimulate food intake. In view of the well-known tight connection between the nutritional state and the reproductive function, in this study we examined a possible role of orexin-A in the generation of ovarian steroid-induced luteinizing hormone (LH) and prolactin (PRL) surges in ovariectomized rats. Experiments were performed on both normally-fed and 3-day-fasted rats. Although fasting led to abolition of both LH and PRL surges, intracerebroventricular administration of orexin-A (0.3 and 3.0 nmol) resulted in a dose-dependent recovery of the hormonal surges. In addition, anti-orexin-A antisera given to normally-fed rats completely abrogated the surges of both hormones. These results demonstrate for the first time a significant participation of orexin-A in the preovulatory LH and PRL surges in the rat.
Kohsaka
A
A
Third Department of Internal Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, 036-8562, Aomori, Japan.
Watanobe
H
H
Kakizaki
Y
Y
Suda
T
T
Schiöth
H B
HB
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002352:Carrier Proteins / Q000276:immunology / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005498:Follicular Phase; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D007986:Luteinizing Hormone / Q000378:metabolism*; D009479:Neuropeptides / Q000276:immunology / Q000502:physiology*; D000068797:Orexins; D010052:Ovariectomy; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D000906:Antibodies; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D011388:Prolactin; D007986:Luteinizing Hormone