Effect of posture on the metabolic clearance rate, plasma concentration and blood production rate of aldosterone in man.

Abstract

Abstract A method for the simultaneous determination of the metabolic clearance rate (MCR) and plasma concentration of aldosterone is described. From these 2 parameters the blood production rate (secretion rate) of aldosterone was calculated. Using this approach the effect of posture on aldosterone secretion and metabolism was studied in 18 normal male subjects, 3 patients with primary aldosteronism and 1 anephric subject. After sitting, there was no significant change in the MCR. The plasma concentration of aldosterone increased 6-fold and the blood production rate increased 5-fold. After standing, the MCR decreased significantly by 23%. The plasma concentration increased 10-fold and the blood production rate increased 8-fold. These results indicate that the increase in secretion rate rather than the decrease in MCR is the major factor regulating plasma aldosterone concentration. All 3 patients with primary aldosteronism had an elevated plasma aldosterone concentration in the supine state, and a correspo...