Vitamin A combined with retinoic acid increases retinol uptake and lung retinyl ester formation in a synergistic manner in neonatal rats

Academic Article


  • Vitamin A (VA) is stored in tissues predominantly as retinyl esters (REs), which provide substrate for the production of bioactive retinoids. Retinoic acid (RA), a principal metabolite, has been shown to induce postnatal lung development. To better understand lung RE storage, we compared VA (given as retinyl palmitate), RA, and a nutrient-metabolite combination, VARA, given orally on postnatal days 5-7, for their ability to increase lung RE in neonatal rats. VARA increased lung RE significantly [∼14, 2.4, 2.1, and <1 nmol/g for VARA, VA, RA, and control (C), respectively; P < 0.001]; the increase by VARA was more than additive compared with the effects of VA and RA alone. Lung histology and morphometry were unchanged. In a 6 h metabolic study, providing [3H]retinol with VARA, compared with VA or C, increased the uptake of newly absorbed 3H by 3-fold, indicating that VARA stimulated the uptake of [3H]retinol and its retention as [3H]RE in neonatal lungs. After cessation of VARA, lung RE remained increased for 9 d afterward, through the period of alveolar development. In conclusion, VARA, a 10:1 nutrient-metabolite combination, increased lung RE significantly compared with VA alone and could be a promising therapeutic option for enhancing the delivery of VA to the lungs. Copyright ©2006 by the American Society for Biochemistry and Molecular Biology, Inc.
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    Digital Object Identifier (doi)

    Author List

  • Ross AC; Ambalavanan N; Zolfaghari R; Li NQ
  • Start Page

  • 1844
  • End Page

  • 1851
  • Volume

  • 47
  • Issue

  • 8