Interrelations between plasma renin activity, aldosterone, and sympathetic nervous system activity in essential hypertension.

Interrelations were investigated between plasma renin activity (PRA), dopamine-beta-hydroxylase activity (DBH), plasma aldosterone (PA), plasma cortisol (PC) and plasma sodium concentration (PNa) in renal vein blood of essential hypertension patients in recumbent position. The patients were divided in compliance with the WHO classification into two groups of stage I and stage II of essential hypertension. In stage I a negative correlation was found in all samples of blood between PA and PNa. This means that in recumbent position in stage I the mechanism of regulation sodium -- aldosterone is maintained. In stage II there were very significant correlations between DBH and PRA in the samples from both renal veins. The left renal vein blood gives the best information about secretion of the left adrenal gland. In stage II in samples from the left renal vein a negative correlation was proved between PA and PRA, and also two very similar negative correlations PA -- DBH and PC -- DBH were demonstrated. The results indicate that in recumbent position in stage II the renin secretion is mainly under the control of the sympathetic nervous system, even if the activity of the latter is depressed, normal or enhanced. The possible negative relation between sympathetic activity and corticosteroid secretion in stage II of essential hypertension is discussed.