Phosphatidylcholine synthesis in the developing small intestine

Abstract

1. Phosphatidylcholine synthesis in the foetal, newborn and adult small intestine of rats was studied by determination of cytidine diphosphocholine-1,2-diacylglycerocholine phosphotransferase (cholinephosphotransferase) and acyl-CoA-1-acyl-sn-glycerol-3-phosphocholine acyltransferase (lysophosphatidylcholine acyltransferase) activities and the incorporation of [1-14C]oleic acid into phosphatidylcholine. 2. Cholinephosphotransferase activity was low in foetal jejunum and ileum, increased 3-4 fold in the ileum by 6 days of age and by 12 days in the jejunum. Jejunal activity remained constant throughout weaning; ileal activity gradually decreased to values 25% of that of the jejunum. 3. Lysophosphatidylcholine acyltransferase activity was high in foetal jejunum and ileum, decreased 70% immediately after birth in the jejunum and increased to adult values by 12 days of age. Ileal activity decreased by 20% after birth, but decreased more rapidly at weaning to 30% of the activity in jejunum. 4. Initial rates and steady-state incorporation of [1-14C]oleic acid into phosphatidylcholine by jejunal rings of 10 day-old rats exceeded that observed in jejunal rings from adult rats by 2-4-fold. 5. In the postnatal jejunum, neither cholinephosphotransferase and lysophosphatidylcholine acyltransferase activities nor oleic acid incorporation were stimulated by cortisone administration in vivo.

Post-natal Growth of the Gastrointestinal Tract of the Siberian Hamster: Morphometric Analysis

“…According to Holtzapple et al. () immediately after birth, the ileum is a more important site of lipoprotein production and in some mammals, including altricial rodents, also plays an important role in the antibody absorption from colostrum and milk. These two processes occur within the villi; thus, the rapid growth in the height of these structures could be associated with increasing their efficiency.…”

Intestinal Lipoprotein Metabolism

“…Although phospholipid from both biliary and dietary sources is available as a polar surface coating for packaging triglyceride into chylomicron particles, developmental studies of lecithin synthesis in the developing rat small intestine have been performed (140). Cholinephosphotransferase activity (responsible for de novo lecithin synthesis) was low in fetal jejunum and ileum and increased threefold to fourfold in the ileum by 6 days of age and increased by 12 days in the jejunum.…”