Figure 1.

DCT-CA-SPAK mice exhibit characteristics of Type 4 RTA, i.e., hyperkalemia with metabolic acidosis and suppressed urinary ammonia excretion. Plasma electrolytes and urine studies were obtained in DCT-CA-SPAK and WT mice before any experimental therapy. n=16 for DCT-CA-SPAK mice and 26 for WT mice for measurements of plasma K⁺ and bicarbonate and urine ammonia and pH, and 16 for each genotype for measurement of urine titratable acid and sum of urine ammonia and titratable acid. Amm + TA, urine ammonia plus titratable acid; DCT-CA-SPAK, mice with early DCT-specific over-expression of constitutively active SPAK; WT, wild-type mice.