| First Author | Reboul E | Year | 2009 |
| Journal | Am J Clin Nutr | Volume | 89 |
| Issue | 1 | Pages | 177-84 |
| PubMed ID | 19056557 | Mgi Jnum | J:163801 |
| Mgi Id | MGI:4829758 | Doi | 10.3945/ajcn.2008.26559 |
| Citation | Reboul E, et al. (2009) ATP-binding cassette transporter A1 is significantly involved in the intestinal absorption of alpha- and gamma-tocopherol but not in that of retinyl palmitate in mice. Am J Clin Nutr 89(1):177-84 |
| abstractText | BACKGROUND: It has long been assumed that newly absorbed vitamin A and E enter the body only via enterocyte-produced chylomicrons. However, recent results in cell cultures have shown that a fraction of alpha-tocopherol is secreted with intestinal HDL. OBJECTIVES: The aims of this study were to identify this transporter and to assess whether it is significantly implicated in the in vivo intestinal absorption of the 2 main dietary forms of vitamin E (ie, alpha- and gamma-tocopherol) and in that of retinyl palmitate (vitamin A). DESIGN: Having performed preliminary experiments in the Caco-2 cell model, we compared fasting and postprandial plasma concentrations of vitamins A and E in mice deficient in ATP-binding cassette A1 (ABCA1) transporter and in wild-type mice. RESULTS: A substantial efflux of alpha- and gamma-tocopherol, but not of retinyl esters, was induced by the presence of apolipoprotein A-I at the basolateral side of Caco-2 monolayers. The efflux of alpha- and gamma-tocopherol was also impaired by glyburide and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. The postprandial response of plasma gamma-tocopherol was 4-fold lower in ABCA1(-/-) mice (P = 0.025) than in wild-type mice, whereas no significant difference was observed for retinyl esters. Fasting plasma alpha-tocopherol, but not vitamin A, concentrations were lower in mice bearing the genetic deletion. CONCLUSIONS: ABCA1 is the transporter responsible for the in vivo secretion of alpha- and gamma-tocopherol with intestinal HDL, and this pathway is significantly implicated in the intestinal absorption and plasma status of vitamin E but not of vitamin A. |
