Testosterone

About: Testosterone is a research topic. Over the lifetime, 23258 publications have been published within this topic receiving 808079 citations. The topic is also known as: 4-androsten-17beta-ol-3-one & 4-Androsten-3-one-17b-ol.

Variations in serum FSH, LH and testosterone levels in male rats from birth to sexual maturity.

Abstract: Serum LH, FSH and testosterone concentrations were measured by radioimmunoassays in male Sprague-Dawley rats from birth to 80 days of age. The levels of FSH were significantly elevated during the first 5 days of postnatal life. An abrupt decline in FSH concentrations occurred during this period, from levels of 800 ng/ml on day 1 to levels of 300 ng/ml on Day 6. Subsequently, FSH levels fluctuated widely until about Days 30 to 45, when a secondary peak of FSH was observed. Thereafter, a decline in FSH levels to those found in adult rats occurred. This decline in FSH levels appears to coincide with the first release of mature spermatozoa from the germinal epithelium in the testis. During the first 30 days of postnatal life, LH and testosterone values appeared to be inversely related to each other and an LH peak and a nadir of testosterone levels was observed between Days 6 and 14 at time corresponding to regression of the fetal generation of interstitial cells. A parallel rise in LH and testosterone levels occurred from Days 30 to sexual maturity and corresponded to the development of the adult generation of intestitial cells.

Androgens stimulate fatty acid synthase in the human prostate cancer cell line LNCaP.

Abstract: In addition to modulation of cell proliferation and stimulation of prostate-specific antigen secretion, one of the most striking effects of androgens on the human prostate cancer cell line LNCaP is the accumulation of neutral lipids. These lipids are synthesized de novo, suggesting that LNCaP cells express all enzymes required for endogenous lipogenesis and that the expression and/or activity of some of these enzymes is affected by androgens. One of the key enzymes involved in lipogenesis is fatty acid synthase (FAS), a potential prognostic enzyme and therapeutic target that is found to be frequently overexpressed in a variety of cancers including prostate cancer. Here, using Northern blot analysis, the gene encoding FAS is shown to be abundantly expressed in LNCaP cells and in two other prostate cancer cell lines tested (PC-3 and DU-145). In LNCaP cells, androgen treatment (10(-8) M R1881) causes a 3-4-fold increase in FAS mRNA levels. Concomitantly with the increase in FAS gene expression, androgens induce a 10-12-fold stimulation of FAS activity. Effects are dose- and time-dependent and follow courses similar to those of the androgen induction of lipid accumulation. In support of the involvement of the androgen receptor, steroid specificity of regulation of FAS activity is in agreement with the aberrant ligand specificity of the mutated androgen receptor in LNCaP cells. Stimulation of FAS activity is inhibited by the antiandrogen Casodex (bicalutamide) and is absent in the androgen receptor-negative cell lines PC-3 and DU-145. Taken together, these data demonstrate that androgens, mediated by the androgen receptor, stimulate the expression and activity of FAS and suggest that stimulation of FAS activity represents at least part of the mechanism by which androgens induce the accumulation of neutral lipids in LNCaP cells.