Testosterone induces Ca2+ influx via non‐genomic surface receptors in activated T cells

Abstract

Using the Fura‐2 method we investigated a possible direct action of testosterone on cytosolic free calcium of splenic T cells isolated from female C57BL/10 mice. Testosterone at physiological concentrations of 1–10 nM induces an increase in [Ca²⁺]_i within seconds, which is due to Ca²⁺ influx and not to Ca²⁺ release from intracellular stores. In contrast, estradiol induces both Ca²⁺ influx and Ca²⁺ release. The testosterone‐induced Ca²⁺ influx is mediated by Ni²⁺‐blockable channels and is not inhibited by cyproterone, a blocker of the classical androgen receptor. Ca²⁺ influx can also be induced by testosterone conjugated to BSA which is impermeable to the plasma membrane. These data indicate a novel mode of direct action of testosterone on T cells which is not mediated through the classical androgen receptor response, but through unconventional plasma membrane receptors.