Vitamin A Supplementation Increases the Uptake of Chylomicron Retinyl Esters into the Brain of Neonatal Rats Raised under Vitamin A-Marginal Conditions.
J Nutr
; 146(9): 1677-83, 2016 09.
Article
em En
| MEDLINE
| ID: mdl-27511933
ABSTRACT
BACKGROUND:
The most rapid phase of brain development occurs during the neonatal period. Vitamin A (VA; retinol) is critical for many aspects of this process, including neurogenesis, synaptic plasticity, learning, and memory formation. However, the metabolism of retinol in the neonatal brain has not been extensively explored.OBJECTIVE:
We examined the uptake of VA into the brain in neonatal rats raised under VA-marginal conditions (control group) and assessed the effect of VA supplementation on the uptake of VA into the brain.METHODS:
Sprague-Dawley neonatal rats (n = 104) nursed by mothers fed a VA-marginal diet were randomly assigned and treated on postnatal day 4 with an oral dose of either VA (6 µg retinyl palmitate/g body weight) or canola oil as the control, both of which contained 1.8 µCi [(3)H]retinol. Pups (n = 4/group at a time) were killed at 13 sampling times from 30 min to 24 d after dosing. The uptake of total retinol, chylomicron-associated retinyl esters (REs), and retinol bound to retinol-binding protein (RBP) was estimated with the use of WinSAAM version 3.0.8.RESULTS:
Total retinol mass in the brain was closely dependent on its mass in plasma over time (r = 0.91; P < 0.001). The uptake of retinol into the brain involved both postprandial chylomicrons and RBP, with RBP delivering most of the retinol in the control group [0.27 nmol/d (RBP) compared with 0.01 nmol/d (chylomicrons)]. VA supplementation increased the fractional uptake of chylomicron REs from 0.3% to 1.2% of plasma pool/d, decreased that of RBP retinol from 0.5% to 0.2% of plasma pool/d, and increased the transfer rate of chylomicron REs from nearly zero to 0.7 nmol/d, causing a day-long elevation in the brain mass of total retinol.CONCLUSION:
Postprandial chylomicrons may be a primary mechanism for delivering a recently ingested large dose of VA to the brain of neonatal rats raised under VA-marginal conditions.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Vitamina A
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Encéfalo
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Quilomícrons
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Suplementos Nutricionais
Idioma:
En
Revista:
J Nutr
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Panamá