Expression of inhibin alpha in the human adrenal gland and adrenocortical tumors

We studied the expression of inhibin alpha-subunit in normal and hyperplast ic adrenal glands, as well as in various adrenocortical tumors. The protein expression of inhibin alpha was performed by immunohistochemistry. Viriliz ing adenomas showed strong immunoreactivity against monoclonal inhibin alph a-subunit antibody, whereas other adenomas were only weakly positive or com pletely negative. In the adrenal cortex no inhibin alpha immunoreactivity w as detected in the zona glomerulosa. Zona fasciculata showed weak staining for inhibin alpha, however, strong immunostaining was detected in zona reti cularis both in normal and hyperplastic adrenal glands. Adrenal medulla was negative for inhibin alpha. In conclusion, we show high expression of inhi bin alpha subunit in zona reticularis of normal and hyperplastic adrenal gl ands as well as strong expression in virilizing adenomas.