title: The biosynthesis of androst-16-enes in boar testis tissue.
abstract: 1. The metabolism of [4-(14)C]pregnenolone to androst-16-enes has been studied in short-term incubations of boar testis tissue. With fresh tissue androsta-5,16-dien-3beta-ol (8%) and 5alpha-androst-16-en-3beta-ol (2%) were formed. Tissue that had been stored at -20 degrees C was still capable of metabolizing pregnenolone to androsta-5,16-dien-3beta-ol. 2. NADPH was essential for the formation of androsta-5,16-dien-3beta-ol from pregnenolone; NADH had less activity and ATP was not necessary for the reaction. 3. [4-(14)C]Androsta-5,16-dien-3beta-ol, prepared biosynthetically from [4-(14)C]pregnenolone, was shown to be converted by boar testis preparations into androsta-4,16-dien-3-one (31%) if NAD(+) was present or into 5alpha-androst-16-en-3beta-ol (4%) if NADPH was present. 4. 17alpha-Hydroxyandrost-4-en-3-one and 3beta,17alpha-dihydroxypregn-5-en-20-one were considered as possible precursors for androst-16-ene formation, but both were shown to be ineffective. 5. No radioactivity was incorporated into androst-5-en-3beta-ol used to trap any corresponding (14)C-labelled compound formed from [4-(14)C]pregnenolone.
mesh_terms: D006907:17-alpha-Hydroxypregnenolone / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000731:Androstanes / Q000096:biosynthesis*; D000818:Animals; D002247:Carbon Isotopes; D002855:Chromatography, Thin Layer; D066298:In Vitro Techniques; D008297:Male; D009249:NADP / Q000378:metabolism; D011284:Pregnenolone / Q000378:metabolism; D013552:Swine; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism; D014316:Tritium
chemical_list: D000731:Androstanes; D002247:Carbon Isotopes; D014316:Tritium; D006907:17-alpha-Hydroxypregnenolone; D013739:Testosterone; D009249:NADP; D011284:Pregnenolone; D000255:Adenosine Triphosphate