Effects of steady‐state plasma vasopressin levels on the distribution of intrarenal blood flow on electrolyte excretion.

Publisher Website
Google Scholar
Abstract
To evaluate the effects of arginine vasopressin (AVP) on the distribution of intrarenal blood flow and on electrolyte excretion, steady-state plasma AVP levels (4.8, 19.1, 44.3 and 100.6 .mu.u[unit]/ml) were produced in anesthetized dogs, which were hydrated to minimize endogenous antidiuretic hormone (ADH) release. The urinary excretion of Na and K increased without change in their filtered loads during AVP infusion. Measurement by the 133Xe washout method revealed diphasic blood flow shifts, as a function of the plasma AVP level, between compartment 1 (outer cortex) and compartment 2 (inner cortex and outer medulla) without change in compartment 3 (inner medulla). The radioactive microsphere (15 .mu.m) method was used with a plasma AVP level of 19.8 .mu.u/ml. Blood flow decreased in the outer cortex and increased in the inner cortex. Total renal blood flow did not change during infusion of AVP. The values measured by 133Xe were lower than those measured by the microsphere method. There was agreement between these 2 independent methods that blood flow shifted from outer to inner cortex, with no change in total renal flow, at similar plasma AVP levels (19.1 and 19.8 .mu.u/ml). The relationship of these intrarenal circulatory changes to the increased electrolyte excretion is discussed.