Effect of circulating norepinephrine on the renin release from the denervated kidney.

The effect of renal denervation on the reactivity of the renin release mechanism to circulating norepinephrine was studied in six dogs with renal autografts. The renin release was determined simultaneously in the transplanted and the untouched kidney. Both kidneys showed an increased release of renin when norepinephrine was given. A slight reduction in renal blood flow and increase in arterial blood pressure was recorded. Propranolol blocked the release of renin induced by norepinephrine without affecting either the reduced blood flow thorugh the autograft or the elevated blood pressure. The denervation of the autotransplanted kidney was histochemically verified. The findings indicate that the renin release induced by circulating norepinephrine is independent of the intrarenal adrenergic nerves, and rather suggest that it is the result of an action of norepinephrine directly on the renin-producing juxtaglomerular cells. In this mechanism a beta-adrenergic receptor system appears to be involved.