Abstract
The influence of age on plasma arginine vasopressin was examined in three groups of healthy men, 25±1 (n=12), 40 (n=23) and 50 years of age (n = 13), respectively. The three groups were comparable in body height, weight, blood pressure, heart rate, serum and urine osmolality, electrolytes and endogenous creatinine clearance. Compared to the 25-year olds, the 50-year old men had more than three times higher basal plasma vasopressin (7.8± 1,4 vs. 2.5±0.6 ng/1, p<0.01), only one-third the plasma renin concentration (0.36±0.05 vs. 1.10±0.33 G. U. X 10-4/ml, p<0.01) and a significantly higher plasma noradrenaline (267±21 vs. 199±19 ng/l, p<0.05) while plasma adrenaline remained essentially unchanged. The 40-year olds had intermediate plasma vasopressin concentrations (4.2±0.6 ng/l). Thus, age is a variable with a substantial effect on plasma concentrations of vasopressin in addition to the well-known effect on renin and noradrenaline. Age must be taken into account in further clinical studies on vasopressin.