HMOX1 and autoimmune pancreatitis: Administration of two daily intraperitoneal doses of cimetidine (15, 30, or 120 mg/kg/day) to the PB/DDC-induced AIP mice resulted in mean hepatic microsomal HO activities of 4.22, 2.61, and 4.12 nmol/h/mg, respectively, none of which were significantly different from those of the saline-treated controls (Figure 2C).