HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Guémené, D. Articles by Williams, J. B. Search for Related Content PubMed PubMed Citation Articles by Guémené, D. Articles by Williams, J. B.

Stimulation of male turkey hypophyses in vitro with chicken (c)LHRH-I, cLHRH-II or porcine (p)LHRH (0·1 µmol/l) using a perifusion technique caused an increase in the release of LH. In this system, cLHRH-II was approximately 2·5-fold more potent than cLHRH-I and pLHRH which were equipotent. The difference was due to a greater amplitude of the response but not to a prolonged action. Hypophyseal desensitization to a subsequent stimulation was induced when the interval between stimulations was 30 min, but did not occur when lengthened to 60 or 120 min.

Injection of a single dose of cLHRH-I or -II in vivo at doses of 10 and 0·1 nmol/kg body weight stimulated increases in the plasma concentration of LH and testosterone initiated within 1 or 10 min after injection respectively. As in vitro, cLHRH-II induced greater responses, which were dose-related, than did cLHRH-I. However, this difference could be attributed to a greater potency of cLHRH-II and to a more prolonged action. At the 10 nmol/kg dose, the shape of the LH response to cLHRH-II changed; it consisted of an initial increase during 10 min after injection, followed by a more sustained phase during which LH levels were still increasing between 20 and 60 min after injection. In contrast, after an injection of cLHRH-I at doses of 10 or 0·1 nmol/kg or cLHRH-II at a dose of 0·1 nmol/kg, LH levels were at a peak within 5 min and thereafter declined gradually. This decrease in LH may therefore simply be related to the disappearance of the LHRH from the circulation or to other unknown actions of cLHRH-II, when high doses are used.

Journal of Endocrinology (1992) 132, 387–393

This article has been cited by other articles:

				Y. Okada, A. Murota-Kawano, S. S. Kakar, and S. J. Winters Evidence that Gonadotropin-Releasing Hormone (GnRH) II Stimulates Luteinizing Hormone and Follicle-Stimulating Hormone Secretion from Monkey Pituitary Cultures by Activating the GnRH I Receptor Biol Reprod, October 1, 2003; 69(4): 1356 - 1361. [Abstract] [Full Text] [PDF]

				Y. Chaiseha, O. M. Youngren, and M. E. El Halawani Vasoactive Intestinal Peptide Secretion by Turkey Hypothalamic Explants Biol Reprod, July 1, 1998; 59(3): 670 - 675. [Abstract] [Full Text]