Interrelationships between the renin-angiotensin-aldosterone system and sympathetic and dopaminergic activities in...

The interrelationships between the renin-aldosterone system and the sympathetic and dopaminergic activities were studied by measuring the plasma renin activity (PRA), plasma aldosterone concentration (PAC), serum prolactin (PRL) concentration, and 24 hr-urinary excretions of adrenaline (Ad), noradrenaline (NA) and dopamine (DA) in elderly normotensive subjects aged 60 to 90 yrs. The PAC showed a significant correlation with NA in the urine (gamma = 0.694, n = 24, p less than 0.001). The PRA also tended to correlate with NA in the urine, although the degree was weak and not significant. The serum PRL concentration showed a significant correlation with DA in the urine (gamma = 0.447, n = 24, p less than 0.05). No significant correlation was observed between DA and PRA or PAC, and between the serum PRL concentration and PRA or PAC. From these results, it is shown that the renin-aldosterone system has a relation to urinary NA excretion, and the existence of an interrelationship between the central dopaminergic activity and urinary DA excretion is suggested.