Fig. 7.

Effect of metabolic acidosis on neonatal rat brush-border membrane vesicle Na⁺/H⁺ exchanger activity. A: Na⁺/H⁺ activity from brush-border membrane vesicles from neonatal rats was measured using the acridine orange technique. Brush-border membrane vesicles from neonatal acidotic rats had a higher Na⁺/H⁺ activity than control. The Na⁺/H⁺ activity was inhibited by 10⁻⁶ M EIPA. B: effect of EIPA on adult rat brush-border membrane vesicle Na⁺/H⁺ exchanger activity. Na⁺/H⁺ exchanger activity was measured in adults in the absence and presence of EIPA. The activity was severalfold greater than that in neonates and was relatively resistant to EIPA. No. of experiments is in parentheses.