Effects of rokitamycin on young rats with hyperbilirubinemia--determination of unbound and brain bilirubin levels and examination for localized yellow discoloration of brain tissue.

The effects of rokitamycin (RKM), a macrolide antibiotic, on young rats with hyperbilirubinemia were investigated. RKM at a dose of 1,000 mg/kg was orally administered to 14-day-old rats with hereditary, non-hemolytic hyperbilirubinemia (homozygous Gunn rats, total plasma bilirubin concentration: about 7 mg/dl). Animals given 10 ml/kg of 0.5% carboxymethyl cellulose (CMC) were used as control. Plasma total bilirubin concentration, plasma unbound bilirubin concentration and cerebellar bilirubin level did not significantly change during 1, 3, 6 and 24 hours after administration of RKM or CMC. There was no significant difference in plasma total bilirubin concentration, plasma unbound bilirubin concentration and cerebellar bilirubin level between RKM-treated and control animals at 1, 3, 6 and 24 hours after the administration. No localized yellow discoloration of the brain tissue (non-cerebellar parts) was noted at 1, 3, 6 and 24 hours after administration of either RKM or CMC.