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Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium.

Publication ,  Journal Article
Katz, ML; Drea, CM; Robison, WG
Published in: Biochimica et biophysica acta
June 1987

Experiments were conducted to determine the influence of dietary levels of vitamin A and alpha-tocopherol on the amounts and composition of retinyl esters in the retinal pigment epithelium of light-adapted albino rats. Groups of rats were fed diets containing alpha-tocopherol and either no retinyl palmitate, adequate retinyl palmitate, or excessive retinyl palmitate. Other groups of rats received diets lacking alpha-tocopherol and containing the same three levels of retinyl palmitate. Retinoic acid was added to diets lacking retinyl palmitate. After 27 weeks, the animals were light-adapted to achieve essentially total visual pigment bleaches, and the neural retinas and retinal pigment epithelium-eyecups were then dissected from each eye for vitamin A ester determinations. Almost all of the retinyl esters were found in the retinal pigment epithelium-eyecup portions of the eyes, mainly as retinyl palmitate and retinyl stearate. Maintaining rats on a vitamin A-deficient, retinoic acid-containing diet led to significant reductions in retinal pigment epithelial retinyl ester levels in rats fed both the vitamin E-supplemented and vitamin E-deficient diets; contrary to expectations, the effect of dietary vitamin A deficiency was more pronounced in the vitamin E-supplemented rats. Vitamin A deficiency in retinoic acid-maintained animals also led to significant reductions in retinyl palmitate-to-stearate ester ratios in the retinal pigment epithelia of both vitamin E-supplemented and vitamin E-deficient rats. Excessive dietary intake of vitamin A had little, if any, effect on retinal pigment epithelial retinyl ester content or composition. Vitamin E deficiency resulted in significant increases in retinal pigment epithelial retinyl palmitate content and in palmitate-to-stearate ester ratios in rats fed all three levels of vitamin A, but had little effect on retinal pigment epithelial retinyl stearate content. In other tissues, vitamin E deficiency has been shown to lower vitamin A levels, and it is widely accepted that this effect is due to autoxidative destruction of vitamin A. The increase in retinal pigment epithelial vitamin A ester levels in response to vitamin E deficiency indicates that vitamin E does not regulate vitamin A levels in this tissue primarily by acting as an antioxidant, but rather may act as an inhibitor of vitamin A uptake and/or storage. The effect of vitamin E on pigment epithelial vitamin A levels may be mediated by the vitamin E-induced change in retinyl palmitate-to-stearate ratios.

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Published In

Biochimica et biophysica acta

DOI

EISSN

1878-2434

ISSN

0006-3002

Publication Date

June 1987

Volume

924

Issue

3

Start / End Page

432 / 441

Related Subject Headings

  • Vitamin E
  • Vitamin A
  • Retinyl Esters
  • Rats, Inbred F344
  • Rats
  • Pigment Epithelium of Eye
  • Male
  • Diterpenes
  • Diet
  • Animals
 

Citation

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MLA
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Katz, M. L., Drea, C. M., & Robison, W. G. (1987). Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium. Biochimica et Biophysica Acta, 924(3), 432–441. https://doi.org/10.1016/0304-4165(87)90157-7
Katz, M. L., C. M. Drea, and W. G. Robison. “Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium.Biochimica et Biophysica Acta 924, no. 3 (June 1987): 432–41. https://doi.org/10.1016/0304-4165(87)90157-7.
Katz ML, Drea CM, Robison WG. Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium. Biochimica et biophysica acta. 1987 Jun;924(3):432–41.
Katz, M. L., et al. “Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium.Biochimica et Biophysica Acta, vol. 924, no. 3, June 1987, pp. 432–41. Epmc, doi:10.1016/0304-4165(87)90157-7.
Katz ML, Drea CM, Robison WG. Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium. Biochimica et biophysica acta. 1987 Jun;924(3):432–441.

Published In

Biochimica et biophysica acta

DOI

EISSN

1878-2434

ISSN

0006-3002

Publication Date

June 1987

Volume

924

Issue

3

Start / End Page

432 / 441

Related Subject Headings

  • Vitamin E
  • Vitamin A
  • Retinyl Esters
  • Rats, Inbred F344
  • Rats
  • Pigment Epithelium of Eye
  • Male
  • Diterpenes
  • Diet
  • Animals