Renal sodium retention and vasopressin induced kaliuresis in ethanol anaesthetised rats

Renal electrolyte excretion has been examined in water loaded ethanol anaesthetised rats receiving continuous iv saline (0.077 m NaCl) infusion. These animals exhibited very low rates of Na+, K+ and Cl− excretion by comparison with Inactin anaesthetised rats. Water loaded Inactin anaesthetised rats also showed a degree of Na retention but both Na+ and K+ excretory rates were higher than in ethanol anaesthetised animals. Plasma aldosterone levels did not differ between ethanol and Inactin anaesthetised groups. Vasopressin administration did not effect Na+ but potentiated K+ excretion in ethanol anaesthetised animals. This contrasted with the potent natriuretic and weak kaliuretic action of vasopressin in water loaded Inactin anaesthetised rats. The significance of abnormal renal electrolyte handling and the marked kaliuretic effect of vasopressin to the use of ethanol anaesthetised animals for vasopressin bioassay is discussed.