Pregnenolone and progesterone metabolism by the testes of Bufo arenarum.
Sliced testis tissue from Bufo arenarum was incubated in the presence of [3H]pregnenolone. Testis fragments were also used for double isotope experiments using [3H]pregnenolone and [14C]progesterone. Specific activities were equated with the addition of radioinert pregnenolone. When yields of radiometabolites were analysed, pregnenolone was found to be a good precursor for C19 steroids such as dehydroepiandrosterone, 5-androsten-3 beta, 17 beta diol, testosterone, 5 alpha-dihydrotestosterone and a C21 steroid, 5 alpha-pregnan-3,20 dione. Progesterone mainly converts to 5 alpha-pregnan-3,20 dione, a steroid with unknown function in amphibians. The 5-ene pathway, including 5-androsten-3 beta, 17 beta diol as intermediate, could be predominant for androgen biosynthesis. Testes bypass not only progesterone but also androstenedione for testosterone biosynthesis.
Canosa
L F
LF
Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina. fcanosa@biolo.bg.fcen.uba.ar
Pozzi
A G
AG
Ceballos
N R
NR
D043582:5-alpha-Dihydroprogesterone; D000728:Androgens / Q000096:biosynthesis; D015114:Androstenediol / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D002022:Bufo arenarum / Q000378:metabolism*; D002250:Carbon Radioisotopes; D003687:Dehydroepiandrosterone / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D011277:Pregnanediones / Q000378:metabolism; D011284:Pregnenolone / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis; D014316:Tritium
D000728:Androgens; D002250:Carbon Radioisotopes; D011277:Pregnanediones; D014316:Tritium; D013739:Testosterone; D000735:Androstenedione; D003687:Dehydroepiandrosterone; D011374:Progesterone; D011284:Pregnenolone; D015114:Androstenediol; D043582:5-alpha-Dihydroprogesterone