Mibolerone (dimethylnortestosterone) or 5 alpha-dihydrostestosterone (DHT) increase intracellular calcium (Ca2+i) of human prostate cancer cells (LNCaP) as early as 2 min after treatment. These effects were concentration-dependent (10(-6)-10(-12) M) and they were blocked by preincubation with hydroxyflutamide (10(-6) M). Verapamil (10(-6) M) also suppressed the mibolerone (10(-6) M)-induced increase in Ca2+i, in cells which were previously exposed to 1 mM CaCl2 introduced in a Ca(2+)-free media. The results indicate that androgens elicit changes in Ca2+i in LNCaP cells as a result of Ca2+ influx through L-type channels in the plasma membrane. Since androgens are involved in the regulation of prostate cell division and growth, these findings suggest that calcium is involved in metabolic and mitogenic responses to steroid hormone in target cells.