Effects of dihydrotestosterone and hydroxyflutamide on androgen receptors in cultured human breast cancer cells (EVSA-T).

The purpose of our study was to evaluate the effects of 5 alpha-dihydrotestosterone (DHT) and hydroxyflutamide (HF), alone or in combination, on androgen receptor (AR) dynamics and on cellular growth in cultured breast cancer cells (EVSA-T). The incubation of cells with DHT increased the concentration of nuclear AR after 24 and 48 h. HF was also able to promote the nuclear accumulation of AR after 24 and 48 h of treatment. When HF-treated cells are incubated with DHT, the nuclear AR concentration is lower than that found in cells treated with DHT alone. We conclude that HF acts by increasing nuclear accumulation of receptor-antiandrogen complexes. Moreover, DHT stimulates cell growth while HF has an inhibitory effect. Thymidine incorporation in cells also increased after DHT treatment and decreased after HF incubation. The HF-induced inhibition of cell growth persisted both after renewal of the medium and after the addition of DHT to cultures. It may be hypothesized that either DHT is converted to inactive metabolites or that HF exerts a persistent inhibitory effect. In the latter case, the antiandrogen action of HF could be exerted by retention of high levels of antiandrogen in cells or by such a depressed protein synthesis that the renewal of growth is slower than the 48 h period studied.

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.