Effect of 17 beta-estradiol on calcium response to phytohaemagglutinin in human lymphocytes.

Pre-treatment of human lymphocytes with 17 beta-estradiol diminishes the increase in concentration of cytosolic free calcium after stimulation with phytohaemagglutinin. The effect is dependent on 17 beta-estradiol concentration and on the preincubation time. The effect is not due to an interaction between 17 beta-estradiol and phytohaemagglutinin, but appears to be a consequence of the binding of the hormone to the cell surface. The effect is specific for 17 beta-estradiol, since the alpha isomer and other steroid hormones (progesterone, testosterone, diethylstilbestrol and 5 alpha-androstan) have no effect. Since the effect of the 17 beta-estradiol can be suppressed by treatment of lymphocytes with ouabain, it appears that the effect of estradiol on the rise of cytosolic calcium induced by phytohaemagglutinin is mediated by the (Na, K)-ATPase.