The influence of a single dose of vasopressin analogs on human renal potassium excretion.

The effect of intranasal administration of 10 micrograms of 1-deamino-8-d-arginine vasopressin (DDAVP) and intravenous administration of 200 micrograms of N-glycyl-glycyl-glycyl-lysin-vasopressin (TGLVP) on urinary concentration (UK) and fractional excretion (FEK) of potassium was investigated in healthy subjects. For comparison the same parameters were followed under conditions of 36-h water-intake restriction. Once the maximally concentrated urine had been reached, the average value of UK after DDAVP administration was 108 +/- 45 mmol/l and after TGLVP administration 102 +/- 48 mmol/l. These values are significantly higher (p less than 0.001) than the average value of UK observed under conditions of water deprivation (58 +/- 22 mol/l). The average value of FEK after DDAVP administration was 14.8 +/- 6.3% and after TGLVP administration, 14.9 +/- 6.5%. These values are also significantly higher (p less than 0.001) than the average values of FEK observed under control conditions (9.3 +/- 5.5%) The effect of DDAVP on UK and FEK was related to the age of the investigated subjects. The most pronounced changes were observed in younger individuals. The influence of vasopressin analogs on UK and FEK could not be explained on the basis of changes in urinary osmolarity, sodium excretion, or fractional water excretion. The results obtained are compatible with the hypothesis that DDAVP and TGLVP increase the tubular secretion of potassium. The mechanism of action has to be elucidated by further research.