Journals of Gerontology Series A: Biological Sciences and Medical Sciences Large Type Edition
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]
Author:
 		Keyword(s):
Year:  Vol:  Page: 

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Google Scholar
Right arrow Articles by Brown, O. A.
Right arrow Articles by Goya, R. G.
Right arrow Articles citing this Article
PubMed
Right arrow PubMed Citation
Right arrow Articles by Brown, O. A.
Right arrow Articles by Goya, R. G.
The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 55:B170-B176 (2000)
© 2000 The Gerontological Society of America

Studies on the Gonadotropin-Releasing Activity of Thymulin

Changes With Age

Oscar A. Browna, Yolanda E. Sosaa, Mireille Dardenneb, Jean-Marie Pléaub and Rodolfo G. Goyaa

a INIBIOLP-Histology B, School of Medicine, National University of La Plata, Argentina
b CNRS URA 1461, Université Paris V, Hôpital Necker, France.

Rodolfo G. Goya, INIBIOLP, Facultad de Medicina, UNLP, CC 455, 1900 La Plata, Argentina E-mail: rgoya{at}netverk.com.ar.

Decision Editor: Jay Roberts, PhD

We assessed the ability of thymulin, a zinc-dependent nonapeptide produced by the thymic epithelial cells, to influence the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from dispersed anterior pituitary (AP) cells from young, adult, and senescent female rats. Perifusion of young and senescent AP cells with thymulin doses of 10-6 to 10-5 M gave a significant stimulatory response for LH but not FSH. Gonadotropin release was always lower in the senescent cells. AP cells from both age groups incubated with 10-8 to 10-3 M thymulin showed a time- and dose-dependent response for both gonadotropins, with a maximal stimulation at 10-7 M. Preincubation of thymulin with an antithymulin serum completely quenched the secretagogue activity of the hormone. Coincubation of thymulin with the secretagogue gonadotropin-releasing hormone (GnRH) revealed a synergistic effect on LH release and an additive effect on the release of FSH. The calcium chelator EGTA blocked the gonadotropin-releasing activity of thymulin in AP cells. The cAMP enhancers, caffeine, NaF, and forskolin significantly increased the thymulin-stimulated release of gonadotropins. The inositol phosphate enhancer LiCl potentiated the action of thymulin on gonadotropins. It is concluded that the gonadotropin-releasing activity documented here for thymulin is an age- and receptor-dependent effect mediated in part by calcium, cAMP, and inositol phosphates.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
All GSA journals The Gerontologist
Journals of Gerontology Series B: Psychological Sciences and Social Sciences
Copyright © 2000 by The Gerontological Society of America.