Studies on bilirubin in bile. Part 1. Excretion of salt-form bilirubin into bile

Salt-form bilirubin, one of the direct bilirubin, was prepared from human bile. The saltform bilirubin dissolved with physiological saline was injected into tail vein of Wister strain rat, heterozygote and homozygote Gunn rat; the bile was collected up to eight hours after loading of the salt-form bilirubin. The amount of salt-form bilirubin excreted into bile and its characterization of excreted salt-form bilirubin was studied by thin layer chromatography and photochemically. The following results were obtained; 1) Absorption maximum of the salt-form bilirubin excreted into bile was observed at 400-430 nm, and absorption maximum of its azo-pigment in pH 14 was at 555-560 nm. The salt-form bilirubin showed negative ninhydrin reaction and benzidine reaction, and the nature of excreted salt-form bilirubin was coincidated with the former reports from our department. According to qualitative reactions and the absorption maxima, the salt-form bilirubin excreted into bile did not change its nature and conjugation. 2) Up to eight hours collection of bile after loading of the salt-form bilirubin amounted under 200 mcg, it was excreted 64.42% in Wister strain rat and 53.81% in heterozygote and homozygote Gunn rat in the average, respectively. The maximum excretion of the salt-form bilirubin was observed in the first two hours after loading in each groups; these portion occupied at 42.9% and 46.5% of the excreted amount in eight hours, respectively. There was no significant differences between the excretion rate of the salt-form bilirubin in Wister strain rat and heterozygote and homozygote Gunn rat