Thyroid Hormone Regulation of Retinoic Acid Synthesis in Brown Adipose Tissue

In mice, alterations to vitamin A status through gene knockout or treatment with pharmacological doses of retinoic acid (RA), the active form of vitamin A, affect overall energy metabolism and body weight. Generally, increases in RA lead to increased metabolism and weight loss, and reductions in RA lead to weight gain. One specific effect is that within brown adipose tissue impaired RA synthesis impairs the tissue\u27s ability to generate heat and thus an organism\u27s ability to maintain normal body weight and temperature. We therefore hypothesize that in a cell model of brown adipose tissue, thyroid hormone (T3), a potent activator of brown adipose function, will also increase RA synthesis through induction of retinol and retinal dehydrogenases. Together, these enzymes synthesize RA from the precursor retinol. Overall, our work contributes to a better understanding of factors that impact both obesity and metabolic disease