Renal electrolyte and fluid handling in the rat following chloroquine and/or ethanol administration

We postulated that chloroquine and/or ethanol affect plasma arginine vasopr essin (AVP) concentrations to alter renal function. Therefore, we studied t he effects of chloroquine and/or ethanol on plasma AVP concentrations and f luid, urinary Na+ and K+ outputs in separate groups of anaesthetized Spragu e-Dawley (SD) rats challenged with a continuous jugular infusion of 0.077 M NaCl at 150 mu l.min(-1). After a 3-h equilibration period, vehicle, chlor oquine (0.06 mu g.min(-1)), ethanol (2.4 or 24 mu g.min(-1)) or both chloro quine and ethanol were added to the infusate after 1 h (control) for 1 h 20 min (treatment). The animals were switched back to the infusate alone for the final 1 h 40 min recovery periods. Urine flow Na+ and K+ excretion rate s were determined at 20-min intervals over the subsequent 4-h postequilibra tion period. Blood was collected from separate groups of animals at the end of treatment period or equivalent time for control animals for measurement of plasma aldosterone and AVP concentrations by radioimmunoassay. Simultan eous chloroquine and ethanol infusion significantly (p < 0.01) increased pl asma chloroquine concentrations in an ethanol dose-dependent manner by comp arison with animals administered chloroquine alone. Chloroquine infusion al one (0.06 mu g.min(-1)) and/or ethanol (2.4 or 24 mu g.min(-1)) elevated pl asma AVP concentrations from 9.73 +/- 1.64 fmol.l(-1) in control rats to 15 .65 +/- 2.49 fmol.l(-1), 17.39 +/- 4.21 fmol.l(-1), and 33.87 +/- 6.18 fmol .l(-1), respectively. Separate administration of chloroquine or ethanol at low dose rates increased urinary Na+ excretion rates. We conclude that the impairment of renal electrolyte handling associated with chloroquine admini stration may be exacerbated by ethanol. (C) 2000 Elsevier Science Inc. All rights reserved.