TESTOSTERONE INDUCES CA2-GENOMIC SURFACE-RECEPTORS IN ACTIVATED T-CELLS( INFLUX VIA NON)

Using the Fura-2 method we investigated a possible direct action of te stosterone 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 c ontrast, estradiol induces both Ca2+ influx and Ca2+ release, The test osterone-induced Ca2+ influx is mediated by Ni2+-blockable channels an d 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 indicat e a novel mode of direct action of testosterone on T cells which is no t mediated through the classical androgen receptor response, but throu gh unconventional plasma membrane receptors. (C) 1997 Federation of Eu ropean Biochemical Societies.