Angiotensin-mediated calcium efflux from adrenal glomerulosa cells

Abstract

The effects of angiotensin II on efflux of radiocalcium and production of aldosterone from dispersed bovine adrenal glomerulosa cells were studied using a flow-through system. Concentrations of angiotensin II between 1.25 x 10-10 and 1.25 x 10-8 M were found to stimulate both radiocalcium efflux and the rate of aldosterone production. The increase in radiocalcium efflux occurred within 1.5-2.5 min after angiotensin addition, reached a peak in 3.0-4.5 min, and then declined to a value slightly greater than control. The initial increase in aldosterone production occurred 3-5 min after the peak of calcium efflux. In cells preloaded with [45Ca] and then perfused for 1 h with a medium containing no calcium, the basal rate of aldosterone production fell to zero. Angiotensin II (1.25 x 10-8 M) caused no increase in aldosterone secretion rate but still caused an efflux of radiocalcium. Exposure of cells to 5 x 10-5 M verapamil blocked the effect of 1.25 x 10-10 M angiotensin on both radiocalci