Mechanism of action of interleukin-1 in modulating gonadotropin secretion. In vivo and in vitro studies.
To obtain further information on the mode of action of interleukin (IL)-1 in modulating gonadotropin secretion, a series of in vivo and in vitro studies has been performed with the beta-isoform of IL-1. IL-1 beta injected in a lateral ventricle of 3-week-castrated female rats resulted in the expected decrease in serum levels of gonadotropins luteinizing hormone (LH), and follicle-stimulating hormone (FSH), accompanied by a decrease in the number of LH-releasing hormone (LHRH) receptors. These results may indicate that the inhibition of gonadotropin release may result from a decrease in the number of LHRH pituitary receptors either through a direct effect on the pituitary or by modulating the release of LHRH from hypothalamic neurons able to induce a reduction in pituitary LHRH receptors. In vitro studies using the GT1-1 cell line, which specifically produces and secretes LHRH, demonstrated that IL-beta stimulates LHRH release but does not influence intracellular levels of LHRH mRNA. These results seem to indicate that IL-1 beta may act at several levels of the nervous machinery leading to gonadotropin secretion, with a series of effects more complex than previously anticipated.
Dondi
D
D
Department of Endocrinology, University of Milano, Italy.
Limonta
P
P
Montagnani Marelli
M
M
Piva
F
F
D000818:Animals; D002460:Cell Line; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015870:Gene Expression / Q000187:drug effects; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D006062:Gonadotropins / Q000378:metabolism*; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D010052:Ovariectomy; D010902:Pituitary Gland / Q000378:metabolism; D051381:Rats; D011966:Receptors, LHRH / Q000378:metabolism; D013997:Time Factors
D006062:Gonadotropins; D007375:Interleukin-1; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone