Adiponectin: A protein hormone produced and secreted exclusively by adipocytes (fat cells) that regulates the metabolism of lipids and glucose. Adiponectin influences the body's response to insulin. Adiponectin also has antiinflammatory effects on the cells lining the walls of blood vessels. High blood levels of adiponectin are associated with a reduced risk of heart attack. Low levels of adiponectin are found in people who are obese (and who are at increased risk of a heart attack). Adipocytes produce and secrete a number of proteins, including leptin, adipsin, properdin, and tumor necrosis factor (TNF). An adipose tissue-specific factor was isolated and termed APM1 (AdiPose Most abundant gene transcript 1). The protein product of APM1 is adiponectin. The APM1 gene maps to chromosome 3q27.