| Abstract: | Abstract. It has been reported that catecholamines stimulate plasma renin activity (PRA) in vivo and in vitro. Yet the respective roles of endogenous epinephrine and norepinephrine are still debated. Therefore two tests were performed in human subjects: the cold pressure and the 2-deoxy-d -glucose tests. During these tests and on a control day, blood samples were taken at short intervals for PRA; in some subjects the excretion of epinephrine (E) and norepinephrine (NE) was also measured. In 9 healthy males the cold pressure test induced an immediate NE response with increase of systolic and diastolic blood pressure without change in the blood glucose concentration. There was no significant change in the mean value of PRA although in four subjects some rise of PRA occurred. The 2-deoxy-d -glucose induced, in response to an intracellular glucopaenia, an E discharge with a rise in the blood glucose concentration. In all 8 healthy males a striking rise of PRA was observed. Neither hyperglycaemia nor the concomitant decline of serum potassium could explain this rise of PRA, since the same changes during oral glucose test were not accompanied by a similar elevation. Patients with Addison's disease of tuberculous origin responded in a normal fashion to the cold pressure test, but failed to present a hyperglycaemia and a rise of PRA in response to 2-deoxy-d -glucose. This indicates that an intact adrenal medulla was required for the last stimulus but not for the former. From these studies in man it would appear that endogenous epinephrine stimulates renin more strongly than norepinephrine. |
