Thyroid Hormones and Metabolism Regulation: Which Role on Brown Adipose Tissue and Browning Process?

Thyroid hormones (THs) are important modulators of many metabolic processes, being strictly associated with the control of energy balance, mainly through activities on the brain, white and brown adipose tissue, skeletal muscle, liver, and pancreas. In this review, the principal mechanisms of TH regulation on metabolic processes will be discussed and THs' relevance in metabolic disease progression will be evaluated, especially in the cardiovascular context and correlated diseases. Moreover, we will discuss THs' regulatory role on metabolic events in white and brown adipose tissue, with a special focus on the process of "browning", which consists of the gradual acquisition by white adipocytes of the physical and functional characteristics of brown adipocytes. The advancements in research on molecular mechanisms and proposed physiopathological relevance of this process will be discussed.