Détermination par chromatographie liquide á haute performance du rétinol et des esters de rétinol dans le cerveau du rat wistar

Abstract

Intervention of vitamin A in several biological process has been known since decades. Retinoids play a role in the maturation of the central nervous system and in the cerebral metabolism but metabolism studies of the vitamin A in the brain are insufficient. In this study the goal is to determine vitamin A and retinyl esters concentrations of the rat brain by high performance liquid chromatography (HPLC). The validation of this HPLC method shows that results are reliable and reproducible. Reproducibility has been assessed with coefficient of variation (2.84% for retinol and 3.78% for retinyl palmitate) and rate of recovery was 95.2 % for retinol and 96,8 for retinyl palmitate. Results show that the retinol and retinyl esters are constituents of the brain of rat. The brain of rat revealed considerable quantities of vitamin A as retinol and as retinyl esters. The retinyl palmitate with 11.77 ± 4.11nmol/g is the most abundant ester in the brain in front of the retinyl linoleate (2.80±1.3 l nmol/g) and of the retinyl stearate with a concentration of 2.11± 0.64 nmol/g. This technique allowed us to note that the vitamin A, as free alcohol and as esters, is a biochemical constituent of the rat brain. The simultaneous existence of the two chemical structures encourages the hypothesis according to which the brain is capable to stock and to convert the two entities. Keywords : Vitamin A, retinol esters, HPLC, brain West African Journal of Pharmacology and Drug Research Vol. 21 (1&2) 2005: pp. 18-21