Thyro-weight: Unlocking the Link between Thyroid Disorders and Weight.

Thyroid hormone is an important determinant of energy expenditure and contributes to appetite regulation, while hormones and cytokines from the adipose tissue act on the CNS to inform on the quantity of energy stores. A continuous interaction between the thyroid hormone and regulatory mechanisms localized in adipose tissue and brain is important for human body weight control and maintenance of optimal energy balance. Direct effects on ATP utilization are a result of thyroid hormone's actions on metabolic cycles and increased cell membrane ion permeability. However, the majority of thyroid hormone induced energy expenditure is thought to be a result of indirect effects, which, in turn, increase capacity for energy expenditure. This review discusses the direct actions of thyroid hormone on energy expenditure, and places special emphasis on the indirect actions of thyroid hormone, which include mitochondrial biogenesis and reduced metabolic efficiency through mitochondrial uncoupling mechanisms.