Reproduction  
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS  
Reproduction (2006) 131 763-769
DOI: 10.1530/rep.1.00807
Copyright © 2006 Society for Reproduction and Fertility
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
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Aguilar, R
Right arrow Articles by Sánchez-Criado, J E
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Aguilar, R
Right arrow Articles by Sánchez-Criado, J E

RESEARCH

Estradiol and its membrane-impermeable conjugate estradiol–BSA inhibit tamoxifen-stimulated prolactin secretion in incubated rat pituitaries

R Aguilar, C Bellido, J C Garrido-Gracia, R Alonso1 and J E Sánchez-Criado

Department of Cellular Biology, Physiology and Immunology, University of Córdoba Avda, Menendez Pidal s/n, 14004 Córdoba, Spain and 1 Department of Physiology, University of La Laguna, Spain

Correspondence should be addressed to J E Sánchez-Criado; Email: fi1sacrj{at}uco.es

In the absence of estrogen (E), the selective E receptor modulator tamoxifen (TX) has two agonist effects in the rat pituitary: induction of progesterone receptor (PR)-dependent GnRH self-priming in the gonadotrope, and stimulation of prolactin (PRL) secretion in the lactotrope. TX-induced gonadotropin (GnRH) self-priming is absent when 10–8 M estradiol-17ß (E2) is added to the incubation medium of pituitaries from TX-treated rats. The present experiments investigated whether PR-independent PRL release into the incubation medium of pituitaries from TX-treated ovariectomized (OVX) rats was affected by E2, and the effect of different ER ligands (ICI182780, TX, estradiol-17{alpha}, E2 –BSA) on TX-stimulated PRL secretion. Moreover, the effect of E2 on TRH-stimulated PRL secretion in pituitaries collected from estradiol benzoate- and TX-treated OVX rats was studied. It was found that: i) incubation with E2 supressed the PRL releasing effect of injected TX; ii) whereas coincubation with the pure anti-E type II ICI182780 antagonized the inhibitory effect of E2, coincubation with the anti-E type I TX did not; iii) estradiol-17{alpha} lacked inhibitory action, whereas a dose-dependent inhibitory effect of both E2 and E2 –BSA was noticed; and iv) TRH stimulatory effect on PRL release in pituitaries from TX-treated rats was blocked by addition of E2 to the medium. Taken together, these data argue in favor of the presence of specific membrane recognition sites for E in the lactotrope involved in steroid-specific E2 inhibition of TX-stimulated PRL secretion.




This article has been cited by other articles:


Home page
 J EndocrinolHome page
J. E Sanchez-Criado, J. C Garrido-Gracia, C. Bellido, R. Aguilar, P. Guelmes, P. Abreu, R. Alonso, I. Barranco, Y. Millan, and J. M. de las Mulas
Oestradiol-17{beta} inhibits tamoxifen-induced LHRH self-priming blocking hormone-dependent and ligand-independent activation of the gonadotrope progesterone receptor in the rat.
J. Endocrinol., July 1, 2006; 190(1): 73 - 84.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS  
Copyright © 2006 by the Society for Reproduction and Fertility.