Reduction of plasma gonadotropin levels and pituitary tumor size by treatment with bromocriptine in a patient with gonadotropinoma.

A pituitary tumor with suprasellar extension was found by magnetic resonance imaging (MRI) in a male with diabetes mellitus. Endocrine examination revealed high plasma follicle-stimulating hormone (FSH) and alpha-subunit levels, which increased with administration of thyrotropin (TSH)-releasing hormone (TRH). Plasma luteinizing hormone (LH) and testosterone levels were low. Pituitary gonadotropin producing tumor was diagnosed. Because the patient refused surgery, bromocriptine was administered and plasma FSH and alpha-subunit rapidly decreased; on MRI the tumor size was gradually reduced. When pituitary operation is not feasible, bromocriptine is one choice of treatment.