In-vivo and in-vitro endocrine investigation of pure gonadal dysgenesis.

Diagnosis of XY pure gonadal dysgenesis was established in a patient of female phenotype, with female internal genitalia, but with a chromosomal constitution of 46 XY. Streak gonads had undergone neoplastic transformation--gonadoblastoma and dysgerminoma. Before operation the concentrations of gonadotrophins in plasma were high and of oestradiol was low. Administration of oestradiol benzoate initially suppressed and then stimulated an increase in the plasma concentration of LH. These changes were not accompanied by changes in blood levels of endogenous sex steroids. A single injection of hCG failed to stimulate steroid secretion. The activities in vitro of steroid-metabolizing enzymes in the dysgenetic gonadal tissue more closely resembled those of ovarian tissue from a premenopausal and from a postmenopausal women than those in testes from two androgen-insensitive patients. However, aromatase activity was higher in the dysgenetic gonads than in the pre or post-menopausal ovaries. Examination of enzymes in genital skin fibroblasts demonstrated normal activities of 3 alpha/beta-beta-hydroxysteroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase (oxidative and reductive directions). However, 5 alpha-reductase activity was low in minces and fibroblasts of genital skin from the patient. Androgen binding was within the range for male controls.