FIGURE 7.
KOb/c renal acid-excretion during 3-day MAc-challenge. 24-h urine collections were obtained for each day of a 3-day MAc-challenge (timepoints “1–3”) and used to assess daily NH4 + excretion (A,B), titratable acid (TA) excretion (C,D), and urine pH (E,F). (A) Daily NH4 + excretion. Under control conditions there was no significant difference in average daily NH4 + excretion between WT and KOb/c mice. Under MAc conditions, there was a significant genotype × time interaction effect (p = 0.049, ANOVA), with KOb/c mice having excreted significantly more NH4 + than WT mice on day 2 of the MAc-challenge. (B) Change in NH4 + excretion between day 1 and 2 (ΔNH4 + day1-2). There was no significant difference between WT and KOb/c ΔNH4 + day1-2 under control conditions. Under MAc conditions, ΔNH4 + day1-2 in KOb/c mice was significantly greater than in WT mice. (C) Daily TA excretion. Under control and MAc conditions, daily average TA excretion was significantly less in KOb/c mice than in WT mice. (D) Change in TA excretion between day 1 and 2 (ΔTA day1-2). There was no significant difference between WT and KOb/c ΔTA day1-2 under control or MAc conditions. (E) Daily urine pH. Under control conditions, the average daily urine pH was significantly greater in KOb/c mice than in WT mice, but under MAc conditions, there was no significant difference in daily average urine pH. (F) Change in urine pH between day 1 and 2 (Δurine pH day1-2). There was no significant difference between WT and KOb/c Δurine pH day1-2 under control or MAc conditions. p-values reported for the main effect of genotype (“G”) and genotype x time (“G*T”) interaction effect in A, C, and E. Diamond symbols in B, D, and F represent average values. *p < 0.05 between WT and KOb/c mice at each day noted, assessed by Student’s 2-tailed unpaired t-test or Mann-Whitney test; ns, non-significant. For n’s in panels A, C, and E, see Table 1. For B, D, and F – [control] WT: n = 11M/9F, KOb/c: n = 11M/7F-[MAc] WT: n = 11M/13F, KOb/c n = 11M/8F.