Testicular endocrine function and androgen-dependent secondary sexual characteristics
were assessed in 283 men 18 to 96 years of age. Mean serum total testosterone levels …

The 24-h mean plasma concentrations of androgens (dihydrotestosterone and total and free
testosterone), estrogens (estrone and estradiol), and gonadotropins (LH and FSH) were …

Age-related changes in Leydig cell number, daily sperm production, and circulating
hormone levels were studied in 15 men between 20 and 48 yr of age and 15 men between …

In order to provide a comprehensive account of pituitary‐testicular function in man, 466
subjects, ranging in age from 2 to 101 years, were studied to examine blood levels of the …

Testosterone and gonadotropins. Several studies demonstrate that the serum testosterone
concentration declines with increasing age. In one cross-sectional study of 83 healthy men …

In an analysis of the role of testicular secretions, it seemed in order first to inquire about the
relation of maleness to sex differences in viability and in pathological conditions occurring in …

Paired testicular volumes and weights, as well as age, height, and weight, were recorded
from a series of 1056 consecutive necropsies on adult males ranging in age from 18 to 96 …

Although alterations of circulating sex steroids have been reported in aging men, it is not
known to what extent reported changes may represent effects of variables other than aging …

An endocrinologic and quantitative histologic study was carried out in 64 elderly men who
underwent orchidectomy owing to prostatic carcinoma. The men were classified into age …

Decreased testicular function occurs as a concomitant of aging in men and is accentuated
by the presence of systemic illness. Previous studies identified an intrinsic Leydig cell defect …