Effect of catecholamines and the renal nerves on renin secretion in anesthetized dogs

Intravenous infusion of either epinephrine (5–6 µg/min) or norepinephrine (12–16 µg/min) during maintenance of a constant renal arterial blood pressure by means of suprarenal aortic constriction, or stimulation of the renal nerves produced essentially the same effects on renal function and renal venous plasma renin concentration, the latter being measured indirectly by bioassaying the pressor activity produced by plasma incubation under standardized conditions. Glomerular filtration rate (GFR), renal plasma flow (RPF), and sodium excretion were decreased, and renin concentration was increased. The induction of osmotic diuresis during catecholamine infusion or renal nerve stimulation reversed or prevented the increase in renin secretion but did not alter the changes in GFR or RPF. It is suggested that the increased renin secretion induced by catecholamines and renal nerve stimulation in nondiuretic dogs might be the indirect result of the decrease in filtered sodium produced by these procedures. However, a direct effect of the catecholamines and renal nerves on the renin-secreting cells cannot be ruled out.