Table 1.

Acid-base and electrolyte status of proton receptor knockout mice (GPR4−/−) and their wild types (GPR4+/+)

GenotypeGPR4+/+GPR4−/−P
Blood
    n1520
    pH7.39 ± 0.017.37 ± 0.010.26
    PCO239.6 ± 0.935.7 ± 1.1b0.006
    PO291.6 ± 4.492.2 ± 4.70.8
    HCO324 ± 0.420.3 ± 0.6c0.00001
    tCO225.1 ± 0.421.7 ± 0.6c0.00004
    K+4.8 ± 0.075.3 ± 0.05c0.0001
    Na+146.3 ± 0.9145.6 ± 1.10.6
    Cl116.3 ± 1119.4 ± 0.6a0.02
    iCa+1.03 ± 0.061.05 ± 0.030.8
    BEecf−1.6 ± 0.5−4.8 ± 0.7c0.001
    anion gap11 ± 0.911.2 ± 0.60.5
    creatinine0.023 ± 0.0020.025 ± 0.0020.5
    BUN24 ± 1.126 ± 1.40.2
Urine
    pH6.08 ± 0.046.37 ± 0.06c0.00003
    osmolarity3057 ± 2964220 ± 371a0.04
    creatinine6.7 ± 0.67.9 ± 0.80.24
    K+/creatinine55.3 ± 2.854.8 ± 2.90.9
    Na+/creatinine24.3 ± 1.324.8 ± 1.50.8
    Cl/creatinine37.8 ± 1.937.7 ± 1.60.9
    Ca2+/creatinine0.14 ± 0.0040.13 ± 0.0030.3
    NH4+/creatinine10.6 ± 0.88.9 ± 0.60.1
    HCO3/creatinine0.17 ± 0.030.18 ± 0.040.95
    TA/creatinine12.2 ± 0.99.7 ± 0.5a0.016
    NAE/creatinine22.6 ± 1.218.4 ± 0.7b0.005
    NAE0.19 ± 0.020.14 ± 0.01a0.04
    creatinine clearance0.29 ± 0.020.23 ± 0.030.1
  • Blood samples were obtained from the tail artery in conscious mice. Urine analyses were performed on samples collected in metabolic cages over 24-hour period. Urine pH and ammonium measurements were also repeated in fresh urine samples to avoid artifacts associated with the prolonged collection of urine in metabolic cages. Concentrations of electrolytes, anion gap, creatinine, and titratable acids (TA) were expressed in mmol/L, NAE was expressed in mmol/24 hours, ratios of urine electrolytes versus creatinine were expressed as mmol/L versus mmol/L, and BUN was expressed in mg/dl, creatinine clearance in ml/min, osmolarity in mOsmol/L, and PCO2 in mmHg.

  • aP < 0.05.

  • bP < 0.01.

  • cP < 0.005.