Progesterone action through aggregation of a receptor on the sperm plasma membrane

Abstract

Rapid steroid effects, reported in several cell types, have pointed out the possibility of non-genomic mechanisms of action, presumably on cell surface receptors. Here we analyzed the effects of antibody-mediated aggregation of a novel type of progesterone receptor on the plasma membrane of human sperm cells. We report that aggregation of hormone-receptor complexes induces Ca²⁺ influx and a Ca²⁺-dependent exocytotic event in this system. These data suggest a possible mechanism for rapid steroid-induced events. Further research is warranted to examine if a similar mechanism is involved in rapid steroid effects in other cell types.