1973 Volume 109 Issue 3 Pages 281-296
Both urine flow rate and urine electrical conductivity were recorded continuously in hydrated alcohol-anesthetized rats, and the patterns of changes in these two induced by intravenous injection of ADH were compared. Although ADH-induced changes in urine flow rate and conductivity were reciprocally related, significant deviation from a simple reciprocal relation was found when a relatively high dose of ADH was given. Dose-response curves as obtained by using the maximum magnitude or the time-integral of the response as the index of the response revealed that the urine-flow method has higher sensitivity to ADH in a relatively low dose range, whereas the conductivity method is superior for the assay of relatively high dose of ADH. Saluresis induced by NaCl-loading or by administration of Furosemide produced parallel increases in both urine flow and conductivity, while a reduction of blood pressure caused parallel decreases. Asphyxia and pentobarbital sodium produced ADH-like (reciprocal type) pattern of changes, but these changes were interpreted as the results of a liberation of endogenous ADH. Diuretic effect of a low dose of ADH, saluretic effect of a moderate dose of ADH, and vascular effect of a high dose of ADH were characterized by the dual recording of urine flow rate and conductivity. It is concluded that the dual reocrding of urine flow rate and conductivity is recommendable for the assay of ADH of a wide range of dose since the renal effect of ADH is of composite nature, and the single recording of either of these urinary factors cannot characterize the ADH action.
