Effects of high vitamin A intake on adipose tissue vitamin A levels in mice with impaired capacity for hepatic vitamin A storage

Abstract

Both lecithin:retinol acyltransferase‐ (Lrat−/−) and cellular retinol‐binding protein type I‐ (CrbpI−/−) deficient mice have impaired hepatic vitamin A storage capacity. To gain insight into relationships between hepatic and adipose vitamin A storage, Lrat−/−, CrbpI−/− and Lrat−/−/CrbpI−/− mice were maintained for 4 wks on the basal AIN‐93M diet or this diet supplemented with 25‐fold excess retinol. Liver and adipose retinol/retinyl ester levels were determined by HPLC. Regardless of diet, no retinyl esters were detected in livers of Lrat−/− and Lrat−/−/CrbpI−/− mice; whereas wild type and CrbpI−/− mice respectively had levels of 363±60 and 162±41 on the basal diet and 4272±828 and 763±267 nmol/g on the excess diet. Adipose tissue total retinol levels for Lrat−/−, CrbpI−/−, Lrat−/−/CrbpI−/− and wild type mice fed the basal diet were respectively 10.2±3.1, 9.9±1.4, 8.2±0.4 and 3.2±0.3 nmol/g. On the excess diet the levels for Lrat−/−, CrbpI−/−, Lrat−/−/CrbpI−/− and wild type mice were respectively 153.6±27.2, 137.7± 43.8, 145.9±16.6, and 34.9±4.7 nmol/g. Thus, impaired capacity to store vitamin A in liver increased adipose accumulation of vitamin A for both basal and excess diet groups.