(obsolete name for chorionic gonadotropin), a substance found in the urine of pregnant female mammals that exerts gonadotropic activity. Gonadotropin is not produced by the pituitary gland, as was earlier supposed, but by the chorionic villi of the placenta. The terms prolan A and prolan B were previously used in endocrinological literature and have been replaced by the terms follicle-stimulating hormone and luteinizing hormone.