Impaired Leydig cell reserve and altered serum androgen binding in the aging male

The hormonal profile of the aging male reveals an associated decrease in free testosterone and 5 alpha-dihydrotestosterone (DHT) levels and increased luteinizing hormone levels. Later events consist of a decrease in total testosterone, stable DHT, and increased follicle-stimulating hormone and estradiol levels. Although most available information supports the concept of impaired Leydig cell reserve, our study suggests some degree of hypothalamic-pituitary dysfunction. The signal for increased androgen binding with age is not clear. There is a great deal of individual variation in the time of onset of these events.