Weight changes and survival curves of B6 and FVB animals deficient in P-gp expression. Changes in body weight (A, B) are expressed from weaning at 4 weeks of age. Survival (C, D) was determined up to 8 months of age. Weights and survival were derived from an N of 8 for the B6, B6.mdr1a−/− and FVB animals, and 7 for the FVB.mdr1a−/−. § Indicates the incidence of diarrhea in FVB.mdr1a−/− animals. * Indicates statistically significant weight loss of P<0.05 in FVB.mdr1a−/− animals when compared to wild type controls, as determined by a Student’s T-test.