Roles of dietary vitamin A in the regulation of hepatic gene expression in response to fasting‐refeeding cycle

Abstract

We have shown that vitamin A (VA) status affects the plasma glucose and lipid levels, and hepatic gene expression in rats. Therefore, we hypothesize that dietary VA intake and its hepatic metabolism regulate the expression of genes involved in glucose and lipid metabolism in response to fasting‐refeeding cycle. Male Zucker lean rats were fed with a VA deficient (VAD) or a VA sufficient (VAS) diet for 8 weeks. The VAD or VAS rats were fed ad libitum, fasted for 48 hours (H) or refed a VAD or VAS diet for 6H. The plasma parameters were measured using commercial kits. The hepatic protein and mRNA levels were respectively examined by Western blot and real‐time PCR. The responses of plasma insulin and leptin levels to the feeding cycle were altered in VAD rats compared to VAS ones. The hepatic mRNA levels of Gck, Srebp‐1c, and Fas were reduced after 48H fasting regardless of VA status. The 6H refeeding of a VAS diet induced their mRNA levels in VAD and VAS rats. However, the 6H refeeding of a VAD diet only induced their expression levels in VAS, but not VAD rats. We conclude that dietary VA and its hepatic metabolism contribute to the regulation of plasma hormone levels and hepatic gene expression in rats.Grant Funding Source: American Heart Association