Bilirubin excretion pattern in manganese-bilirubin cholestasis.

Impaired bilirubin excretion has been investigated as the possible mechanism for the cholestasis observed following the injection of manganese and bilirubin in rats. We studied the biliary excretion pattern of bilirubin in bile under both cholestatic (manganese plus bilirubin) and noncholestatic (manganese or bilirubin alone; manganese plus bilirubin plus sulfobromophthalein) conditions using a diazotization reaction and this layer chromatography. The accumulation of non-C-1-glucuronides or of nonglucuronoconjugates of bilirubin in bile does not seem to be responsible for the cholestasis. The altered biliary bilirubin metabolic pattern of the azodipyrollic fractions observed during manganese-bilirubin cholestasis appeared to be the result of the cholestasis, rather than its cause.