This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via Google Scholar Google Scholar Articles by LU, K. H. Articles by YEN, S. S. C. Search for Related Content PubMed PubMed Citation Articles by LU, K. H. Articles by YEN, S. S. C.

The Effect of an Antiserum to Luteinizing Hormone- Releasing Hormone on the Progesterone-Induced Luteinizing Hormone Surge in Ovariectomized, Estrogen- Primed Rats^*

Department of Reproductive Medicine, University of California San Diego, La Jolla, California 92093

Address requests for reprints to: Dr. K. H. Lu, Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, UCLA School of Medicine, Los Angeles, California 90024.

Abstract

A rabbit antiserum to synthetic LHRH was shown to be specific to rat hypothalamic LHRH, as revealed by binding studies (RIA). The present study was undertaken to determine the effects of this antiserum (LHRH-AS) on the progesterone-induced LH surge in ovariectomized rats primed with estrogen and on the proestrous LH surge in cycling females. An ip injection of 0.2 ml LHRH-AS at 1200 h on proestrus completely inhibited the preovulatory rise in serum LH from 1700–1800 h. In long term ovariectomized rats, a sc injection of estradiol benzoate reduced serum LH levels by 50% at 1200 h on the third day. Subsequent administration of progesterone elicited a LH surge, with peak LH values 4–6 h after progesterone. However, concurrent administration of LHRH-AS effectively prevented the increase in LH release by progesterone, and an iv injection of LHRH-AS was shown to be more effective than ip administration in inhibiting the progesterone stimulation of LH release. Although estrogen and progesterone may induce a change in pituitary responsiveness to hypothalamic LHRH in ovariectomized rats, the present study provides evidence that tonic and/or increased LHRH release is required for the acute increase in LH release caused by progesterone (Endocrinology 106: 867, 1980)

Footnotes

^* This work was supported by Rockefeller Foundation Grant RF- 75029, University of California San Diego Academic Senate Biomedical Research Grant 6622, and NIH Grant HD-12303-02.

Received April 2, 1979.