FASTING-RELATED HYPERBILIRUBINEMIA IN RATS - THE EFFECT OF DECREASED INTESTINAL MOTILITY

Background Br Aims: Fasting increases serum bilirubin levels in both h umans and vats. Because the pathogenesis of fasting hyperbilirubinemia is not fully understood, the effect of fasting on disposition of bile pigments was investigated in vats. Methods: Bilirubin and urobilinoge n were determined in excreta, bile, plasma, and liver tissues of faste d Gunn and Wistar vats. Results: Fasting increased the intestinal tran sit time of Wistar rats. As a result, the fecal output of bile pigment s was decreased by food deprivation. In contrast, the intestinal conte nt of total bile pigments was augmented in both Wistar and Gunn rats. This finding was paralleled by the increase of serum bilirubin concent ration in both rat strains. A similar increment of serum bilirubin lev els was observed after injection of bilirubin into the cecum of Wistar rats. Furthermore, biliary efflux of bilirubin in Wistar rats was inc reased after 48 hours of fasting. Intubation of nonabsorbable bulk to fasted Wistar rats prevented the increase of sevum bilrubin levels dur ing a 48-hour period of food deprivation. Conclusions: Fasting decreas es intestinal motility and elimination of bile pigments. Accumulation of bilirubin in the intestine during fasting allows enhanced enterohep atic circulation and results in an increased reflux to plasma. This se ems to be a major factor involved in fasting-induced hyperbilirubinemi a.