STUDIES OF IN VITRO STEROID METABOLISM BY TESTIS TISSUE FROM ‘COMPLETE’ AND ‘INCOMPLETE’ FORMS OF TESTICULAR FEMINIZATION

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Abstract
SUMMARY: The in vitro steroid metabolism of testicular tissue from seven cases of testicular feminization was studied. Using radioactive steroid substrates of both C21 and C19 configurations, kinetic studies of these tissues showed that the major pathway of testosterone production was via the Δ5 pathway, i.e. pregnenolone → 17α‐hydroxy‐pregneolone → dehydroepiandrosterone → androstenedione and androstenediol → testosterone, with the accumulation of dehydroepiandrosterone and androstenediol. This accumulation of dehydroepiandrosterone and androstenediol does not occur in similar incubations of normal human testis tissue.The seven cases of testicular feminization were classified as ‘complete’ or ‘incomplete’ forms of the syndrome by reference to clinical data and the histology of the testicular tissue. It was concluded that the biochemical differences between the two forms of the syndrome were the greater production and accumulation of C21 and C19Δ4 steroids from the C21 and C19Δ5 steroid precursors indicating the relatively greater activity of the C21‐3β‐hydroxysteroid dehydrogenase‐isomerase enzyme in the ‘incomplete’ form.