Fat cells produce a lot of factors that are important for healthy metabolism and circulation. When fat cells malfunction, they make too many of these factors, and that can raise the risk of heart disease and diabetes (type 2 or adult-onset form). We are interested in what causes fat cell to malfunction. We have discovered that TSH (thyroid stimulating hormone), known for its role in controlling the thyroid, also acts on fat cells and can cause fat cell to malfunction. We want to study how TSH activates the fat cells, because other research shows that people that have high TSH levels (~5-10% of the population; a condition called subclinical hypothyroidism) have a higher risk for heart disease. We will obtain fat cells from volunteers, place them in dishes in the lab, and study how TSH causes the over-production of these factors that promote artery blockages. We will also study the levels of these factors from blood samples of patients who receive short-term TSH treatment (as a test for thyroid cancer care).