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 …

Although basal serum LH and FSH levels have been shown to increase with age in men,
there is evidence that aging may impair pituitary gonadotropin secretion to some extent. We …

The influence of aging on the responsiveness to sex steroid hormones in men was studied
by comparing circulating gonadotropin concentrations, pulsatile LH release, and sex …

A cross-sectional study on 220 men, aged 41–93 yr, was conducted to determine whether
age-related changes in circulating pituitary and gonadal hormone levels are related to …

Abstract Seven men, 21–30 years old, and six men, 72–90 years old, were given human
chorionic gonadotropin (HCG), 3,000 units a day for four days. The concentration of 17β …

Serum testosterone (T) levels in men decline with age while serum LH levels, as measured
by RIA, increase. To assess if the decline in serum T levels in healthy aging men is …

To assess the capacity of aging human Leydig cells to respond to intramuscular injection of
hCG, six healthy men, 68 to 86 years old, and eight healthy younger subjects, 25 to 42 years …

Cross-sectional studies have demonstrated a decline in testosterone and free and
bioavailable testosterone with age. This occurs in a majority of older persons without an …

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 …

To evaluate the hypothesis that endocrine profiles change with aging independently of
specific disease states, we examined the age trends of 17 major sex hormones, metabolites …