EFFECT OF ENDOTHELIUM-DERIVED RELAXING FACTOR ON RENIN SECRETION FROMISOLATED MOUSE RENAL JUXTAGLOMERULAR CELLS

This study aimed to examine the direct influence of native endothelium derived relaxing factor (EDRF) on renin secretion. To this end isolat ed mouse renal juxtaglomerular cells were cocultured with bovine aorti c endothelial cells which produced and released significant amounts of EDRF as assayed by guanylate cyclase activities which were measured s eparately in endothelial and juxtaglomerular cells as well as in the c ocultures of juxtaglomerular with endothelial cells. EDRF production w as blunted in the absence of extracellular L-arginine and in the prese nce of N(omega)nitro-L-arginine (L-NAG; 200 muM). Inhibition of endoth elial EDRF production by removal of arginine or addition Of L-NAG was associated with a significant decrease of renin secretion from the coc ultures while the same regimen had no effect on renin secretion from J G cells alone. Exogeneous generation of nitric oxide by the addition o f sodium nitroprusside (100 mum) stimulated renin secretion in the coc ultures both at normal and inhibited EDRF formation as well as from ju xtaglomerular cells alone. These findings suggest that native EDRF rel eased from vascular endothelial cells is a stimulatory signal for reni n secretion from renal juxtaglomerular cells.