Effect of synthetic atrial natriuretic peptide on rat renal juxtaglomerular cells.

We examined the effect of synthetic atrial natriuretic peptide (ANP) on unstimulated renin release from rat renal juxtaglomerular cells. Using renal cortical cell cultures containing 80-90% juxtaglomerular cells, we found that ANP strongly inhibited renin release from the cells in a dose-dependent fashion. Half-maximal inhibition was observed at 10(-11) mol/l ANP. Furthermore, ANP produced a rise in the intracellular concentration of cyclic guanosine monophosphate (cGMP) and a fall in the concentration of cyclic adenosine monophosphate (cAMP). Data indicated that the inhibition of renin release by ANP was related to the rise in cGMP and not to the fall of cAMP. Atrial natriuretic peptide (10(-10) mol/l) had no influence on the transmembrane calcium influx nor did it alter the intracellular calcium concentration of the juxtaglomerular cell. We found, however, that the inhibitory effect of ANP on renin release could be attenuated by the calcium channel blocker verapamil. Our results suggest that ANP inhibits renin release from juxtaglomerular cells by a mechanism that is mediated by cGMP; the mechanism is not linked to any alteration in intracellular calcium concentration but requires a normal level of calcium.