In the past 10 years hirsutism has been the object of a considerable number of fundamental studies. It provides endocrinologists with an experimental model for the investigation of androgen secretion, metabolism and mechanism of action. Plasma androgen assay, free testosterone measurement, hepatic and extrahepatic androgen metabolic clearance and androgen metabolism in the skin are the different steps which were studied by many groups and represent valuable parameters of the mechanisms of hirsutism. Determination of the origin of androgen oversecretion has become easier by technical progress...