METABOLISM OF [PREGNENOLONE-17-H-2 INTO 5-[17-BETA-H-2,17-ALPHA-O-18]ANDROSTENE-3-BETA,17-ALPHA-DIOL AND OTHER PRODUCTS BY INCUBATION WITH THE MICROSOMAL FRACTION OF BOAR TESTIS UNDER O-18(2) ATMOSPHERE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 575  (1) , 37-45
Abstract
[17-2H]Pregnenolone was incubated with the microsomal fraction of boar testis under an 18O2 atmosphere. The metabolites were analyzed by gas chromatography-mass spectrometry and the following 6 metabolites labeled with 2H or 18O (or both) were identified: 17.alpha.-[17-180]hydroxypregnenolone, [17-180]dehydroepiandrosterone, 5-[17-180]androstene-3.beta.,17.beta.-diol, 16.alpha.-[16-180]-hydroxy[17-2H]pregnenolone, 5-[17.beta.-2H,17-180]androstene-3.beta.,17.alpha.-diol and 5,16-[17-2H]androstadien-3.beta.-ol. The time course of the formation of these metabolites from pregnenolone was also studied using 14C-labeled substrate. The first 3 metabolites evidently were synthesized by a well-documented pathway; pregnenolone .fwdarw. 17.alpha.-hydroxypregnenolone .fwdarw. dehydroepiandrosterone .fwdarw. 5-androstene-3.beta.,17.beta.-diol.sbd., and that 16.alpha.-hydroxypregnenolone, 5-androstene-3.beta.,17.alpha.-diol and 5,16-androstadien-3.beta.-ol were synthesized from [17-2H]pregnenolone with retention of 17-2H.