Is renin secretion governed by the calcium permeability of the juxtaglomerular cell membrane?

Using cell cultures rich in renal juxtaglomerular cells we found that a change of the intracellular c-AMP concentration is not a prerequisite for an alteration of the renin secretion rate. Modulators of renin secretion including activators of the adenylate cyclase, however, altered the calcium permeability of the cellular plasma membrane in a way that stimulators of renin secretion lowered the calcium permeability and vice versa. Our results suggest that renin secretion is controlled by the intracellular calcium concentration and not by c-AMP. We postulate that modulators of renin secretion act by changing the calcium permeability of the cell membrane.