[Variations in urinary antidiuretic hormone levels related to sodium intake (author's transl)]

Eighteen healthy male subjects, were investigated under normal sodium intake and after 5 days of high and low sodium intake. Under normal sodium intake, the following mean values were observed -- plasma osmolality (Posm): 294 +/- 5 mOsm/kg -- plasma volume (Vp): 33.9 +/- 4,3 ml/kg -- urinary sodium output (UNa.V): 173 +/- 73 mEq/24 h -- urinary antidiuretic hormone (A.D.H.): 68.8 +/- 35.6 ng/24 h. Under low sodium intake these values decreased to -- Posm: 289 +/- 4 m Osm/kg -- Vp: 32.7 +/- 3.2 ml/kg -- UNa.V: 12 +/- 9 mEq/24 h -- A.D.H.: 40.9 +/- 16.3 ng/24 h. Under high sodium intake these values increased to -- Posm: 298 +/- 5 m Osm/kg -- Vp: 36.3 +/- 4.1 ml/kg -- UNa.V: 325 +/- 67 mEq/24 h -- A.D.H.: 118.2 +/- 45.5 NG/24 H. Highly significant correlations are found between Posm and A.D.H. and between the Posm or A.D.H. and UNa.V. Interest is focused on UNa.V since the correlation between A.D.H. and UNa.V (r = 0.78) is more significant than that between A.D.H. and Posm (r = 0.47). Overriding of Posm on Vp in the regulation of A.D.H. secretion is again demonstrated. Plasma renin activity decrease when A.D.H. increase.