Dissociated changes of pituitary luteinizing hormone-releasing hormone (LHRH) receptors and responsiveness to the neurohormones induced by 17β-estradiol and LHRH in vivo in the rat

L. Ferland, B. Marchetti, C. Seguin, F. A. Lefebvre, J. J. Reeves, F. Labrie

Research output: Contribution to journalArticlepeer-review

Abstract

A single injection of 17β-estradiol into castrated male or female rats results in an initial decrease in plasma concentrations of LH and pituitary responsivenesses to LHRH, followed by a rapid return to normal or slightly elevated values. Under such experimental conditions, no acute change of binding of [125I-labeled D-Ser(TBU)6]LHRH ethylamide to anterior pituitary homogenate could be observed. Moreover, the self-priming effect of LHRH, as illustrated by a 10-fold increase in the LH response to a second injection of LHRH in the afternoon of proestrus, is accompanied by a 40% loss of pituitary LHRH receptors. During the estrous cycle, a 100% increase in pituitary LHRH receptors is already found on diestrus II, while the maximal LH responsiveness to LHRH occurs later, namely on the afternoon of proestrus. The present findings of a dissociation between changes in LHRH receptor levels and LH responsiveness to the neurohormones suggest that postreceptor events play a predominant role in the control of gonadotropin secretion by sex steroids and LHRH itself. Moreover, LHRH can cause an acute down-regulation of its own receptor in the anterior pituitary gland.

Original languageEnglish
Pages (from-to)87-93
Number of pages7
JournalEndocrinology
Volume109
Issue number1
Publication statusPublished - 1981

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

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