BILE-ACID CONCENTRATIONS IN SERUM AND DUODENAL ASPIRATES OF HEALTHY PRETERM INFANTS - EFFECTS OF GESTATIONAL AND POSTNATAL AGE

In 41 healthy human-milk-fed preterm infants the preprandial total bil e acid (BA) concentrations in serum and duodenal juice were simultaneo us measured during the first 60 days of life. The infants were subdivi ded into Preterm infants four groups according to their gestational ag e: 6 infants with a gestational age of 27 and 28 weeks, 7 infants with a gestational age of 29 and 30 weeks, 21 infants with a gestational a ge of 31 and 32 weeks and 7 infants with a gestational age of 33 and 3 4 weeks. The BA levels were enzymatically determined using 3-alpha-hyd roxysteroid dehydrogenase. In the duodenal juice, cholic acid (CA), ch enodeoxycholic acid (CDCA), deoxycholic acid and lithocholic acid were separately quantified by thin-layer chromatography. During the first month of life; the Serum BA concentrations increased significantly wit h postnatal age (p < 0.01) but remained nearly constant during the sec ond month of life. In the duodenal aspirates, the BA concentrations in creased continuously up to the end of the observation period (p < 0.00 1). In the duodenal aspirates, the CA/CDCA ratio was high immediately after birth and decreased significantly with increasing postnatal age (p < 0.001). During the first weeks of life, the BA levels were prefer entially conjugated with taurine, but in spite of the taurine-rich die t during the whole observation period the taurine/glycine ratio decrea sed with postnatal age (p < 0.001). In all samples of duodenal juice, the sum of primary BA was > 98% of total 3-alpha-hydroxy-BA. These dat a indicate that the establishment of an intestinal microbial flora nec essary for intestinal BA transformation and the development of the ent erohepatic BA circulation lasts some months of postnatal life. The ser um BA concentration reflects hepatic synthesis, intestinal absorption, renal excretion and hepatocellular transport into bile in a very comp lex way which may Limit the diagnostic value of serum BA during this t ime. Additionally, a duodenal BA concentration below 4 mmol/l, as foun d in this study during the first 2 weeks of life, may be of clinical i mportance due to its possible effects on fat absorption.