Dietary vitamin A modulates lecithin-retinol acyltransferase activity in developing chick intestine

Retinol absorbed and generated from beta-carotene requires to be esterified by lecithin-retinol acyltransferase (LRAT) in intestinal absorptive cells. To characterize developmental changes in retinol absorptive capability in intestine, we determined LRAT activity and the amount of its retinol donor, cellular retinol-binding protein, type two (CRBP(II)) in the duodenum of developing chicks. The LRAT activity in duodenal microsomes was very low at 18- and 20-day chick embryo, but exhibited a rapid (15-fold) increase during 48 h around hatching, which occurred in parallel with the abrupt elevation of the content of CRBP(II) in chick duodenum. To examine whether dietary vitamin A affects the developmental change in LRAT activity and CRBP(II) content, 1-day-old chicks were pair-fed vitamin A-depleted or vitamin A-supplemented diet for 14 days. The chicks fed vitamin A-depleted diet showed significantly reduced LRAT activity and CRBP(II) in duodenum as early as 3 days after the start of the vitamin A-depleted diet. Changing the diet from vitamin A-depleted to vitamin A-supplemented diet led to an increase in duodenal LRAT activity within 24 h, while serum retinol concentration remained unchanged. These results suggest that duodenal LRAT activity and CRBP(II) are modulated by dietary vitamin A during the perinatal period.