The endocrinology of testicular tumors.

The endocrine manifestations of testicular tumors can be produced by one of three mehcansims: (1) direct synthesis of androgens or estrogens by the tumors; (2) synthesis of gonadotropins that stimulate secondary secretion of androgens or estrogens; (3) alteration of the peripheral metabolism of androgens. In this manuscript we have discussed these mechanisms in relationship to steroid-secreting tumors and gonadotrepin-secreting tumors. In postpubertal males, the most common manifestation of these tumors is the production of gynecomastia. Because the breast is a target organ for the action of both androgens and estrogens, gynecomastia occurs when there is an alterartion in the normal androgen/estrogen ratio. Consequently, gynecomastia may be produced by either deficient androgen production or excessive estrogen secretion. The endocrinology of testicular tumors is a fascinating subject and recent development of sensitiv specific radioimmunoassays for the measurement of tumor markers has opened a new area of investigation into the biology of these neoplasms.