[Mechanism of delayed electrolyte excretion as affected by phenobarbital]

Phenobarbital in a dose of 20 mg/kg administered for 3 days lowered renal sodium excretion after an increase in the amount of extracellular liquid induced by different methods: by intravenous injection chloride isotonic solution in an amount of 3% of body mass, by warmed tap water or salt (0.45% solution) loads given in the same quantity. The drug exerted no marked effect on renal sensitivity to natriuretic factor. The decreased sodium excretion in the conditions under consideration might be accounted for by phenobarbital capacity to inhibit the formation or activation of the natriuretic factor in the liver.