Altered expression of both β-carotene 15,15' monooxygenase and lecithin:retinol acyltransferase in obese Zucker rats.

Retinol and its active derivative retinoic acid have an important role in development, reproduction, immunity, and cell proliferation/differentiation. Obesity and dyslipidemia are risk factors for cardiovascular disease that may affect hepatic homeostasis. It is unclear whether the expression of retinol-related proteins is affected and influences the retinol status in obesity and dyslipidemia. The aim of this study was to evaluate the retinol status and expression of retinol-metabolizing enzymes and binding protein in obese and dyslipidemic fa/fa (Zucker) rats. We examined the expression of genes for β-carotene 15,15' monooxygenase (BCM), lecithin:retinol acyltransferase (LRAT), cellular retinol binding protein-I (CRBP-I), and cytochrome P450 26A1 (CYP26A1) in fa/fa rats and lean control rats. We also measured the retinol level in plasma and liver samples from both groups. Plasma retinol levels in fa/fa rats were increased compared with lean rats, while hepatic retinol levels were similar in both groups. In obese and dyslipidemic fa/fa rats, intestinal BCM gene expression was increased, whereas hepatic LRAT gene expression was deceased. There was no difference in hepatic CRBP-I and CYP26A1 gene expression between fa/fa rats and lean rats. Altered expression of BCM and LRAT genes may affect plasma retinol status in obesity and dyslipidemia.