Weight gain in mice treated with ritonavir. At six weeks of age, male and female wild type (C57BL/6) (top) or LDL-R null mice (bottom) were administered ritonavir (15 μg/day) or vehicle (0.01% ethanol) through the drinking water for six weeks. Mice were weighed at the beginning and at the conclusion of the study. Bars represent the mean +/- SEM, n = 6–8. * = significantly different from vehicle (p < 0.05).