SLC26A4 and cystic fibrosis: In a remarkably similar manner, CF mice developed a significantly higher serum HCO3- concentration vs. wildtype (WT) animals when placed on a salt deficient diet (with the serum HCO3- concentration increasing to 29.2 mEq/L in CF mice vs. 26.7 in WT; p<0.03) further supporting the critical role that pendrin plays in both volume regulation and acid base balance (4).