Plasma renin activity in primary and secondary depression.

Plasma renin activity (PRA), both in supine and standing position, was investigated in primary and secondary depressed patients. After orthostatic stimulation (standing position) primary depressed patients showed PRA values significantly lower than did those with secondary depression. The authors stress the importance of the peripheral sympathetic system in the control of renin release and discuss the data obtained in the light of some evidence in the literature indicating a possible impairment of transmitter turnover in central and peripheral noradrenergic synapses in the pathogenesis of primary depression.