Fig. 2.

Time course of urinary ${\text{NH}}_4^{+}$ excretion in acetazolamide (ACTZ) treatment versus NH₄Cl loading. A: time course of urinary ${\text{NH}}_4^{+}$ excretion in rats loaded with NH₄Cl versus rats treated with ACTZ suspended in vehicle 1 (ACTZ-V1) or ACTZ dissolved in vehicle 2 (ACTZ-V2). *P < 0.03 vs. baseline (time 0); £P < 0.01 vs. ACTZ-V2. B: urinary ${\text{NH}}_4^{+}$ excretion was measured in urine collected 6 or 14 days after treatment of rats with ACTZ-V1 or ACTZ-V2 or loaded with NH₄Cl compared with their vehicles or control, respectively. @P < 0.001 vs. vehicle 2 or control; ¥P < 0.05 vs. vehicle 1 or vehicle 2; #P < 0.04 vs. 6 days; ¶P < 0.0001 vs. control. C: fold increase in ${\text{NH}}_4^{+}$ excretion on days 6 and 14 in each treatment. ${\text{NH}}_4^{+}$ excretion increased by ~11-fold in NH₄Cl-loaded rats but only by ~2-fold in ACTZ-treated rats despite a similar degree of metabolic acidosis during the first 6 days of treatment. #P < 0.04 vs. 6 days; §P < 0.001 vs. the same period of ACTZ treatment. D: time course of urine pH in rats loaded with NH₄Cl and rats treated with ACTZ dissolved in vehicle (ACTZ-V2). **P < 0.01 vs. baseline (time 0); *P < 0.05 vs. baseline (time 0) or vs. vehicle 2. n = 5–10 rats in each group as indicated above.