INVESTIGATION INTO INTRAERYTHROCYTIC AND EXTRAERYTHROCYTIC ACID-BASE AND ELECTROLYTE CHANGES AFTER LONG-TERM AMMONIUM-CHLORIDE ADMINISTRATION IN DOGS

Objectives-To investigate the effect of ammonium chloride-induced urin e acidification on acid-base status (ABS) of blood, plasma, and erythr ocytes, and to compare the diagnostic value of acid-base analysis for erythrocytes with that for blood and plasma. Design-Ammonium chloride (100 mg/kg of body weight) was administered orally every 12 hours for 8 consecutive days. The ABS was determined daily in venous blood, plas ma, and lysed, packed erythrocytes (erythrolysate) and in urine. In pl asma and erythrocytes, concentrations of sodium (Na+) and potassium (K +) were analyzed. Animals-16 clinically normal (8 treated and 8 contro l) dogs. Procedure-The acid-base analysis (standard pH, standard bicar bonate concentration, base excess, and carbon dioxide tension) in bloo d, plasma, and erythrocytes was determined by use of the CO2, O-2 gas equilibration method. Determination of urine ABS (pH, concentrations o f acids and bases, net acid-base excretion, and base-acid quotient) wa s performed by titration methods. Determination of concentrations of N a+ and K+ in erythrocytes was performed by flame photometry, and in pl asma, by use of ion-specific electrodes. Results-Ammonium chloride cau sed metabolic acidosis in blood and plasma, but no change of ABS in er ythrocytes. The concentrations of K+ in plasma and erythrocytes did no t change in treated dogs; however, the concentrations of Na+ in plasma and erythrocytes decreased significantly (P < 0.05) after ammonium ch loride administration. Urinary acid excretion increased significantly (P < 0.05) in treated dogs; urine pH was between 4.51 and 5.49 at ail times. Conclusions-Ammonium chloride administration (100 mg/kg, PO, q 12 h) causes substantial blood and urine acidification but does not in fluence erythrocyte ABS. In this study, determination of erythrocyte A BS did not provide any additional benefit in diagnosing of blood.