Gas chromatographic-mass spectrometric study of metabolites of C21 and C19 steroids in neonatal porcine testicular microsomes.
Microsomal fractions obtained from testes of 3-week-old piglets have been incubated, separately, with progesterone, 17-hydroxyprogesterone, 5-pregnene-3 beta,20 beta-diol, 16 alpha-hydroxypregnenolone, 5-androstene-3 beta,17 alpha-diol and dehydro-epiandrosterone. The metabolites, after derivatization, have been separated by capillary gas chromatography and identified by mass spectrometry. Quantification was by selected ion monitoring. Progesterone was shown to be 17-hydroxylated and also converted into 4,16-androstadien-3-one (androstadienone). The major metabolite of 17-hydroxyprogesterone was 4-androstene-3,17-dione (4-androstenedione), but little, if any, androstadienone was formed, indicating that this particular biosynthesis did not require 17-hydroxylation. The metabolites of 5-pregnene-3 beta, 20 beta-diol were found to be 17-hydroxypregnenolone, 3 beta-hydroxy-5,16-pregnadien-20-one (16-dehydropregnenolone) and 5,16-androstadien-3 beta-ol. Dehydroepiandrosterone and 5-androstene-3 beta,17 alpha-diol were interconvertible but neither steroid acted as a substrate for 16-androstene formation. However, dehydroepiandrosterone was metabolized to a small quantity of 4-androstenedione. Under the conditions used, no metabolites of 16 alpha-hydroxypregnenolone could be detected. The present results, together with those obtained earlier, indicate that the neonatal porcine testis has the capacity to synthesize weak androgens, mainly by the 4-en-3-oxo steroid pathway. Although 16-androstenes cannot be formed from C19 steroids, progesterone served as a substrate and may be converted directly to androstadienone, without being 17-hydroxylated first. The pathway to 5,16-androstadien-3 beta-ol, however, involves 17-hydroxypregnenolone and 16-dehydropregnenolone as intermediates.
Kwan
T K
TK
Taylor
N F
NF
Watson
D
D
Gower
D B
DB
D006907:17-alpha-Hydroxypregnenolone / Q000378:metabolism; D019326:17-alpha-Hydroxyprogesterone; D015114:Androstenediol / Q000378:metabolism; D000737:Androstenols / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D003687:Dehydroepiandrosterone / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006908:Hydroxyprogesterones / Q000378:metabolism; D008297:Male; D008861:Microsomes / Q000378:metabolism; D011278:Pregnanes / Q000378:metabolism*; D011284:Pregnenolone / Q000031:analogs & derivatives / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D013552:Swine; D013737:Testis / Q000378:metabolism*
D000737:Androstenols; D006908:Hydroxyprogesterones; D011278:Pregnanes; D006907:17-alpha-Hydroxypregnenolone; D003687:Dehydroepiandrosterone; D011374:Progesterone; D019326:17-alpha-Hydroxyprogesterone; D011284:Pregnenolone; C009033:5-pregnene-3,20-diol; D015114:Androstenediol