Vasopressin Regulation and Renal Fluid and Electrolyte Handling in Rat Models of Acute and Chronic Alcohol Exposure

Abstract

Abstract : Fluid and electrolyte balance is affected differently at different stages of alcohol use. In this study, we examine the role of vasopressin (VP), an important hormone in body fluid regulation, in the physiological response to alcohol. A transient decrease in circulating VP levels occurs immediately after acute alcohol administration, but VP levels return to baseline levels while alcohol is still present in the blood, and there is no prolonged deficiency of VP associated with blood alcohol levels. Rather, alcohol-induced changes in renal responsiveness to VP appear to be responsible for the pattern of diuresis impaired water excretion, and recovery in the different phases of alcohol exposure. Up- and down-regulation of renal VP V2 receptors involved with renal tubular water reabsorption cause differentially altered renal function in the different phases of alcohol exposure. Further, this alcohol-induced renal receptor regulation is specific to the V2 receptors in the inner medulla region of the kidney. In addition, chronic alcohol exposure disrupts the relationships between VP synthesis, brain VP Vi receptors, and blood tonicity. Thus, alcohol-induced changes in VP regulation may affect the ability to respond to physiologic stimuli. Sensitivity of the VP system is currently being further examined with salt load stimulation studies.