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Vitamin A Supplementation Redirects the Flow of Retinyl Esters from Peripheral to Central Organs in Neonatal Rats Raised under Vitamin A‐Marginal Conditions
Author(s) -
Hodges Joanna K.,
Tan Libo,
Green Michael H,
Ross A. Catharine
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.32.3
Subject(s) - retinol , retinyl palmitate , vitamin , medicine , endocrinology , retinol binding protein , vitamin a deficiency , biology , chemistry
Background Vitamin A (VA, retinol) supplementation is used to reduce child mortality in countries with high rates of malnutrition. Existing research suggests that neonates (<1 mo old) may have a limited capacity to store VA in organs other than the liver; however, the knowledge about VA distribution and kinetics in individual non‐hepatic organs is limited. Objective We examined retinol uptake and turnover in non‐hepatic organs, including the skin, brain and adipose tissue, in neonatal rats without and after VA supplementation in the amount equivalent to that which has been given to human infants. Methods Sprague‐Dawley neonatal rats ( n = 104) were nursed by mothers fed a VA‐marginal diet (0.35 mg retinol/kg diet) and treated on postnatal day (P) 4 with an oral dose of either VA (6 μg retinyl palmitate/g body weight) or canola oil (control), both containing 1.8 μCi of [ 3 H]retinol. Subsequently, pups ( n = 4/group/time) were euthanized at 13 times from 30 min to 24 d after dosing. The fractional and absolute transfer of chylomicron retinyl esters (CM‐REs), retinol‐binding protein‐bound retinol (RBP‐ROH) and total retinol were estimated in WinSAAM. Results VA supplementation redirected the flow of CM‐REs from peripheral to central organs and accumulated mainly in the liver. The RBP‐ROH released from the liver was acquired mainly by the peripheral tissues but not retained efficiently causing repeated recycling of retinol between plasma and tissues (541 vs. 5 times in the supplemented vs. control group) and its rapid turnover in all organs, except the brain and white adipose tissue. Retinol stores in the liver lasted for ~2 weeks before being gradually transferred to other organs. Conclusions Vitamin A supplementation administered in a single high dose during the first few days after birth is readily acquired but not retained in the peripheral tissues of neonatal rats suggesting that a more frequent, lower‐dose supplementation may be necessary to maintain adequate VA levels in the rapidly developing neonatal organs. Support or Funding Information Supported by NIH grant HD‐066982