Changes in bilirubins in human prenatal development

Abstract

A densitometric method has been developed for the quantification of azodipyrroles derived from dog bile pigments treated with diazotized ethyl anthranilate. This method was used to estimate the bilirubins in bile and meconium from foetuses of 14-36 weeks gestation. The proportion of the bilirubins in foetal bile changed during gestation. (a) No bile pigments were found until 14 weeks. (b) Between 14 and 15 weeks bilirubin-IXβ was the only bile pigment detected. (c) At 16-17 weeks some unconjugated bilirubin-IXα was found in the bile, but up to 20 weeks bilirubin-IXβ was the predominant bilirubin in the bile. (d) At about 20 weeks glucose, xylose, and an unidentified bilirubin-IXα monoconjugate were found in the bile. (e) Between 20 and 23 weeks bilirubin-IXα glucuronide appeared in the bile. (f) At 30 weeks monoconjugates of bilirubin-IXα were the predominant bilirubins in the bile. (g) Only in full-term foetuses was bilirubin-IXα monoglucuronide the major bilirubin derivative.