Inhibitory effect of circulating norepinephrine on epinephrine-induced renin secretion

The potential role of circulating catecholamines in the regulation of plasma renin concentration (PRC) was evaluated in conscious rats. PRC was very responsive to minor increases in circulating levels of epinephrine but a dose-response relationship was not seen. Circulating norepinephrine in concentrations within physiologic limits (up to 60-80-fold base line) was without effect on basal PRC. When the catecholamines were infused together in approximately equimolar concentrations, norepinephrine completely abolished the PRC rise induced by epinephrine. It is concluded that, in the rat, the circulating catecholamines contribute to the control of PRC by modulating renin secretion through stimulation-inhibition mechanisms.