androst-16-en-3-one and 16-androstene

This study examined the relationship between sulfoconjugation and the degree to which 5alpha-androstenone can accumulate in fat. Analysis of the unconjugated and sulfoconjugated fractions of peripheral plasma from 25 mature Yorkshire boars and testicular vein plasma from an additional 20 mature Yorkshire boars revealed that the majority of 5alpha-androstenone is present as a sulfoconjugate, reaching levels up to 69 +/- 4.3 and 72 +/- 6.2%, respectively, relative to its unconjugated form. The presence of this steroid in the sulfoconjugate fraction was confirmed by gas chromatography-mass spectrometry. Plasma concentrations of 5alpha-androstenone in the sulfoconjugate fraction were negatively correlated (r = -0.36; P < 0.01) with the concentrations of 5alpha-androstenone in fat. High concentrations of 5alpha-androstenone in the sulfate fraction were only associated with animals that had fat androstenone concentrations < 0.5 microg/g. In addition, there was a positive correlation (r = 0.31; P < 0.01) between the concentrations of unconjugated 5alpha-androstenone in plasma and 5alpha-androstenone in fat. These findings indicate that the levels of the sulfoconjugated form present in the peripheral plasma influence the accumulation of 5alpha-androstenone in fat. The specific sulfotransferase enzyme involved in sulfoconjugating these steroids was identified by incubating Leydig cells with specific sulfotransferase inhibitors for 8 h. It was discovered that the enzyme responsible for the sulfoconjugation of the 16-androstene steroids is hydroxysteroid sulfotransferase. Hydroxysteroid sulfotransferase may play a significant role in determining the levels of sulfated 16-androstene steroids present in plasma. The results of this study indicate that sulfoconjugation may serve to regulate the quantity of unconjugated 5alpha-androstenone present in the circulation and thus available for accumulation. Animals with a decreased ability to sulfoconjugate 5alpha-androstenone would have a subsequent increase in the levels of unconjugated 5alpha-androstenone in circulation, allowing for the accumulation of high levels in fat and thereby potentially leading to the development of boar taint.

Topics: Adipose Tissue; Androstenes; Animals; Estrone; Ethylamines; Gas Chromatography-Mass Spectrometry; Leydig Cells; Male; Oximes; Sulfotransferases; Swine; Trimethylsilyl Compounds

Homogenates of histologically normal human testis from three men were incubated separately with pregnenolone, 16-dehydropregnenolone, 5alpha-pregnane-3,20-dione, 3beta-hydroxy-5alpha-pregnan-20-one and androsta-5,16-dien-3beta-ol (androstadienol) in the presence of NADPH in a study of androst-16-ene and androgen biosynthesis. After the addition of internal standards and initial extraction and purification, metabolites were identified using gas chromatography-mass spectrometry (GC-MS) and monitoring selectively for three principal ions in each case at the appropriate GC retention time. Quantification was achieved by comparison with calibration lines for authentic steroids, together with the appropriate internal standards, prepared by monitoring three ion fragments for each analyte. In all experiments, androstadienol was found to be the major androst-16-ene metabolite of pregnenolone (seven times the control, i.e. endogenous, quantity; 19.8 +/- 3 ng/100 mg homogenate protein, mean +/- SEM, n = 9). Pregnenolone was also converted to androsta-4,16-dien-3-one (androstadienone) with three times the endogenous quantity (44 +/- 10 ng/100 mg homogenate protein, mean +/- SEM, n = 9) being formed. The formation of testosterone occurred only in trace amounts in the incubations of testis taken from one man (a 69-yr-old) but appreciable yields (six times endogenous levels 90 +/- 7 ng/100 mg homogenate protein, mean +/- SEM, n = 9) were found with testes from two younger men. Only traces of 5alpha-dihydrotestosterone were detected. Using androstadienol as the substrate, androstadienone was shown to be the major metabolite (approximately 10 times greater than control incubations) together with 5alpha-androst-16-en-3alpha- and 3beta-ols at approximately twice the endogenous quantities (5 ng/100 mg homogenate protein). In some incubations with androstadienol, 5alpha-androst-16-en-3-one (5alpha-androstenone) was formed (32 +/- 1 ng/100 mg homogenate protein/h; mean +/- SEM, n = 3); surprisingly, no endogenous 5alpha-androstenone could be detected. No evidence was obtained for the production of testosterone or 5alpha-DHT from androstadienol. Using cytosolic fractions of human testis, specific (displaceable) binding of 5alpha-androstenone was determined, with binding sites of approximately 200 fmol/mg tissue and a Ka of approximately 8 nmol/l.

Topics: 5-alpha-Dihydroprogesterone; Adult; Aged; Androgens; Androstenes; Androstenols; Chromatography, Gas; Cytosol; Humans; Male; Mass Spectrometry; Middle Aged; Pregnanediones; Pregnanolone; Pregnenolone; Testis; Testosterone