STEROID METABOLISM OF A SERTOLI CELL TUMOUR OF THE TESTIS OF A DOG WITH FEMINIZATION AND ALOPECIA AND OF THE NORMAL CANINE TESTIS

Abstract

SUMMARY: The metabolism of [7α-³H]pregnenolone and [4-¹⁴C]dehydroepiandrosterone (DHA) by a Sertoli cell tumour of the testis from a dog with signs of feminization has been studied in vitro and compared with the metabolism of the normal canine testis. The tumour formed oestrone and oestradiol-17β from DHA thus providing direct evidence for the synthesis of oestrogen by this type of neoplasm. Relative or complete inactivity of several enzyme systems involved in the synthesis of testosterone was found in the tumour tissue, and the conversion of either precursor to testosterone was considerably less than in the normal testis. Suggestive evidence is presented for the occurrence of steroid-specific 17α-hydroxylase and 3β-hydroxysteroid dehydrogenase-isomerase systems in canine testicular tissue. The formation of sulphates of pregnenolone and DHA was shown both in normal and in neoplastic tissues and, in addition, the tumour either formed the sulphate of 17α-hydroxypregnenolone or caused the 17α-hydroxylation of pregnenolone sulphate.