Participation of atrial natriuretic peptide (hANP) levels and arginine vasopressin (AVP) in aged persons with nocturia

Abstract

The associations of human atrial natriuretic peptide (hANP) and arginine vasopressin (AVP) with nocturia in two groups of elderly individuals were investigated. Plasma hANP and AVP levels were determined at 8:00, 14:00, 20:00, 2:00 and 8:00 (2nd day) in 15 healthy younger elderly individuals and 30 elderly individuals who showed no abnormal physical findings. Urine volume, urinary Na and K levels, and urinary osomotic pressure were also determined every 6 hours at the above-mentioned times. The maximum diameter of the inferior vena cava (IVC) in the inferior portion of the confluence of the hepatic veins was determined at 14:00, 20:00 and 2:00 in 11 younger elderly individuals and 17 elderly individuals. The mean hANP level was significantly higher in the elderly group than in the younger elderly group, and the mean AVP level was significantly higher in the younger elderly group than in the elderly group. There were no significant differences in diurnal variation in hANP between daytime and night among the younger elderly individuals, but the hANP level was significantly increased during the night in the elderly individuals. The AVP level was significantly higher at night than during the daytime in the younger elderly individuals, while it was significantly decreased at night in the elderly individuals. Although there was no marked diurnal variation in the IVC in any of the younger elderly individuals, IVC diameter was significantly increased at night in the elderly individuals. Urine volume was high during the daytime in the younger elderly group, and increased during the night in the elderly group. The increase in body fluid and elevation of hANP over the time between evening and night, and the decrease in AVP accompanying these increases were considered to lead to the increase in urine volume during the night, and this increase is considered to be a factor in nocturia.