Abstract
Oliguria is the physiologic response traditionally ascribed to antidiuretic hormone. Under certain conditions, however, intravenous administration of vasopressin has been observed to yield diuresis rather than antidiuresis. | While the mechanism and pertinent details of the antidiuretic response have been amply elaborated, our concepts about the diuretic response still remain vague and the opinions thereon, controversial. | This diuretic effect was first believed to be the simple result of alterations in renal hemodynamics. Later it was considered a tubular effect or a phenomenon secondary to saluresis. Some data indicate that diuresis observed in connection with the stimulation of volume receptors (changes of intrathoracic blood volume) is linked with a decrease of endogenous vasopressin blood concentration; hence, with a presumable decrease in the renal action of the hormone. Recently aldosterone has been implicated in the dichotamous effect of vasopressin. Supposedly the presence of aldosterone is necessary for the antidiuretic action, and its absence or low blood concentration would thus allow a diuretic effect.