Androgen receptors in normal and pathological thyroids.

The purpose of this study was to determine the presence of cytosolic and nuclear androgen receptors (AR) in both normal and nodular thyroid tissues from twelve women and six men. Samples of benign thyroid nodules and corresponding surrounding normal tissue were processed by the single saturation point assay, using [3H] R1881 ([3H] Methyltrienolone) at final concentration of 5 nM. The results show the presence of AR (cytosolic and/or nuclear) in all examined tissue samples. The nuclear AR content was higher (p less than 0.01) in normal rather than in nodular thyroid tissues. The same pattern was observed when nuclear AR were analyzed according to the sex. In addition, nuclear AR content was significantly (p less than 0.05) higher in normal thyroid tissue from men than from women. Our data suggest an androgen influence on thyroid tissue. If androgens are supposed to exert an antagonist role on estrogen actions also in thyroid tissue, the presence of higher nuclear AR concentration in the male rather than in the female normal thyroid may justify the lower incidence of thyroid diseases in men. Moreover, the lower AR levels found in male as well as in female nodular and goitrous tissues support the hypothesis that androgens may act with an antagonist mechanism on thyroid growth.