In vitro secretion of deoxycorticosterone by a benign Leydig cell tumor of the testis

We evaluated the in vitro steroidogenic potential of a benign Leydig cell tumor of the testis. Tumor tissue was found to secrete deoxycorticosterone, progesterone, 17 alpha-hydroxyprogesterone, estradiol and testosterone into the medium. No corticosterone or aldosterone was detected. The ratio of progesterone to 17 alpha-hydroxyprogesterone was 4:1, consistent with a partial enzymatic block of 17 alpha-hydroxylase. The finding of deoxycorticosterone indicates the presence of 21-hydroxylase activity within the tumor. The high local levels of estrogen produced by Leydig cell tumors may induce this enzyme system and, together with the elevated concentrations of progesterone serving as substrate, may provide a favorable hormonal milieu for extra-adrenal deoxycorticosterone production by these neoplasms.