SECRETION OF 19-HYDROXYANDROSTENEDIONE AND 19-HYDROXYTESTOSTERONE BY PORCINE LEYDIG-CELLS INVITRO AND INVIVO

19-Hydroxytestosterone and 19-hydroxyandrostenedione have been identif ied as secretory products of the testes in the mature male domestic pi g. Their isolation and identification were made by reverse-phase high- performance liquid chromatography and capillary gas chromatography-mas s spectrometry (CGC-MS) of extracts from testicular vein blood and med ia of incubations with Leydig cells. Blood was collected from veins on the surface of the testes of anaesthetized boars. Collagenase-dispers ed Percoll-purified cells (> 90% pure) were incubated (20 x 10(6) cell s/flask) with androstenedione (8-75 mumol/1) or [H-3]androstenedione ( 5 x 10(6) c.p.m.) for < 60 min. Steroids were recovered from plasma or media by solid-phase extraction and the unconjugated fractions chroma tographed isocratically in two solvent systems (acetonitrile: water, 3 7: 63 (v/v) and methanol: water, 70:30 (v/v)) before CGC-MS analysis. 19-Hydroxytestosterone was present in greater quantities than 19-hydro xyandrostenedione in testicular vein blood; it was also seen as a quan titatively significant metabolite of unlabelled and radioactive andros tenedione in the incubation studies. The demonstration of the secretio n of 19-hydroxyandrogens from porcine testes thus raises questions con cerning the physiological significance of a testicular, rather than an adrenal, secretion of these compounds.