CLINICAL STUDY Effect of aging on serum gonadotropin levels in healthy subjects and patients with nonfunctioning pituitary adenomas

Objective: Nonfunctioning pituitary adenomas (NFPA), which represent about one-quarter of human pituitary tumors, occur in middle or old age. Determination of gonadotropin levels, which are not expected to be high during the early postmenopause in normal women and which are low in women with NFPA, is important to distinguishing hypogonadal status due to the normal decline of gonadal function from that due to hypothlalamic-pituitary dysfunction. The aim of the study was to verify whether this difference still persists in old subjects, despite the physiological decline of gonadotropins in the last decades of life. Design and methods: The study included 154 healthy subjects (aged 50–104 years) and 47 patients with NFPA (aged 50–80 years). Blood samples were collected after an overnight fast and hormone levels were measured by two immunofluorimetric assays. Results: In healthy women the highest serum levels of gonadotropins were present in the 50–60 year age group, with a slight but progressive age-associated decrease in serum FSH and LH being observed thereafter. In healthy men serum gonadotropin levels were stable up to 70 years, increased up to 75– 85 years and thereafter gradually decreasing. Female patients with NFPA showed levels of gonado