alexa Steroid binding and metabolism in the luteinizing hormone-releasing hormone-producing neuronal cell line GT1-1.
Diabetes & Endocrinology

Diabetes & Endocrinology

Journal of Steroids & Hormonal Science

Author(s): Poletti A, Melcangi RC, NegriCesi P, Maggi R, Martini L

Abstract Share this page

Abstract LHRH synthesis and release are modulated in vivo by gonadal steroids. Although immunocytochemical and autoradiographic studies failed to detect appreciable amounts of estrogen or androgen receptor in LHRH-producing neurons, the recent finding that the promoter region of the LHRH gene contains several steroid hormone-responsive elements indicates a possible direct effect of sex steroids on these specialized neurons. The immortalized LHRH-producing neuronal cell line, GT1, which became recently available, may allow the study of LHRH dynamics. The presence of specific binding sites for estrogen and androgens as well as the presence of the two major enzymatic pathways involved in modulation of androgen action (the 5 alpha-reductase/3 alpha-hydroxysteroid dehydrogenase and the aromatase) have been studied in the GT1-1 clone. High affinity, low capacity binding sites for [3H]estradiol (Kd, 0.11 nM; binding capacity, 6.2 fmol/mg protein) and for a ligand of the androgen receptor, [3H]R1881 (Kd, 0.054 nM; binding capacity, 9.58 fmol/mg protein), have been identified in this cell line. A 2-fold induction of androgen-binding sites has been observed after 3 days of treatment of GT1-1 cells with estradiol (1 microM), indicating that the estradiol binding is probably linked to a functional estrogen receptor. Aromatase and 5 alpha-reductase/3 alpha-hydroxysteroid dehydrogenase activities have been also tested in GT1-1 cells. Under the culture conditions adopted, no detectable aromatization of [1 beta 3H]delta 4-androstenedione to estrone was observed using the tritiated water method. On the other hand, GT1-1 cells efficiently converted testosterone into dihydrotestosterone and subsequently into 5 alpha-androstan-3 alpha,17 beta-diol. In conclusion, GT1-1 cells possess several elements of the machinery through which sex steroids may influence LHRH dynamics. This article was published in Endocrinology and referenced in Journal of Steroids & Hormonal Science

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version