Journal article
Insulin-like growth factor-I augments gonadotropin-stimulated androgen biosynthesis by cultured rat testicular cells
Molecular and cellular endocrinology, Vol.52(1), pp.27-34
1987
DOI: 10.1016/0303-7207(87)90093-1
PMID: 2957258
Abstract
In addition to the well-known growth stimulating effects of insulin-like growth factors (IGFs), recent studies suggest that these peptides may also modulate the differentiated functions of endocrine cells. Thus, in the present studies, we have investigated the actions of IGFs on androgen biosynthesis by cultured testicular cells. Treatment of cells obtained from adult hypophysectomized rats with LH (1 ng/ml) stimulated testosterone production 60-fold over basal levels. In contrast, treatment with either synthetic human IGF-I or IGF-II failed to stimulate androgen production. However, concomitant treatment of the LH-containing cultures with increasing doses of IGF-I (10–500 ng/ml) augmented testosterone production up to 70% over that seen with LH alone (ED
50 = 67 ng/ml). Similar effects were obtained with IGF-II but this peptide was about 10-fold less potent than IGF-I. In addition, these peptides also stimulated the accumulation of pregnenolone and progesterone in the culture medium. Additional studies demonstrated specific binding of [
125I]iodo-IGF-I to testicular cells. This binding was competed by IGF-related peptides with the potency order IGF-II = IGF-I > insulin whereas unrelated peptides did not compete. The cellular localization of these receptors was examined in testicular cells separated on a metrizamide density gradient. IGF-I receptors were evenly distributed between two cell peaks containing subpopulations of Leydig cells whereas much less binding was found in other testicular cell types. Coupled with recent findings indicating testicular production of IGF-I, the present results suggest that this peptide may act as a positive intratesticular modulator of Leydig cell differentiation.
Details
- Title: Subtitle
- Insulin-like growth factor-I augments gonadotropin-stimulated androgen biosynthesis by cultured rat testicular cells
- Creators
- Barry G. Kasson - University of California, San DiegoAaron J.W. Hsueh - University of California, San Diego
- Resource Type
- Journal article
- Publication Details
- Molecular and cellular endocrinology, Vol.52(1), pp.27-34
- Publisher
- Elsevier Ireland Ltd
- DOI
- 10.1016/0303-7207(87)90093-1
- PMID
- 2957258
- ISSN
- 0303-7207
- eISSN
- 1872-8057
- Language
- English
- Date published
- 1987
- Academic Unit
- Neuroscience and Pharmacology
- Record Identifier
- 9984303744602771
Metrics
7 Record Views