To assess the integrity of growth hormone (GH) secretion with age, plasma GH levels were measured in 44 men, 22 to 81 yr old, after an overnight fast, following an intravenous “pulse” of glucose and after arginine infusion. Relative adipose content was derived from weight and estimates of lean body mass by measurement of endogenous 40 potassium emission. With advancing age, there were increases in both relative adipose mass and fasting blood sugar. In contrast, plasma GH levels after an overnight fast [“basal”], after a glucose “pulse,” and following arginine infusion were not significantly altered with aging. Although there was a tendency towards diminished response to arginine in the elderly subjects, this was attributed to the increase in adipose mass. These findings are in agreement with previous studies indicating a preservation of pituitary release of GH with aging.