Acute effect of ethanol on renal electrolyte excretion in rats

Abstract

The purpose of this study was to investigate the renal handling of sodium and potassium in rats during an acute ethanol (ETOH) administration and to relate any observed changes to alterations in renin-aldosterone secretion. Eight male Wistar rats, 7 to 8 weeks of age, were injected intraperitoneally (IP) with 1.0 g/kg body wt. ETOH (15% v/v, 95% ETOH in saline, pH 6.98, osmolality 284 mOsm/kg). Blood ETOH levels were 159 ± 16 (Mean ± SEM) and 120 ± 12 mg/dl, 10 and 30 min after the ETOH injection respectively ( p<0.05). Control animals were given either an equal volume (1.77 ml/100 g body wt.) of 0.9% saline (n = 6) or 5% dextrose solution (n = 4) with similar pH and osmolality. Following ETOH administration blood pH, urine pH, plasma bicarbonate (HCO 3) concentration declined significantly ( p<0.01) while glomerular filtration rate (GFR) and hematocrit (Hct) remained unchanged ( p = 0.1). Mean fractional sodium excretion (FE Na), fractional potassium excretion (FE K), and osmolar clearance (Cosm) fell significantly despite an increase in plasma sodium ( p<0.01), potassium ( p<0.05) and osmolality concentrations ( p<0.05). There was no significant change in plasma aldosterone concentration (PA) or plasma renin activity (PRA) following the ETOH administration. No difference in GFR, FE Na, FE K, Cosm, blood pH, urine pH, plasma electrolytes, PA, or PRA was observed following the saline or dextrose injections. In conclusion, acute ETOH administration in rats alters renal sodium and potassium excretion independent of changes in GFR, PA, PRA or plasma volume as reflected by Hct.