Aging in humans is accompanied by a progressive decline in the secretion of the adrenal androgens dehydroepiandrosterone (DHEA) and DHEA sulfate (DS), paralleling that of the GH-insulin-like growth factor-I (GH-IGF-I) axis. Although the functional relationship of the decline of the GH-IGF-I system and catabolism is recognized, the biological role of DHEA in human aging remains undefined. To test the hypothesis that the decline in DHEA may contribute to the shift from anabolism to catabolism associated with aging, we studied the effect of a replacement dose of DHEA in 13 men and 17 women, 40-70 yr of age. A randomized placebo-controlled cross-over trial of nightly oral DHEA administration (50 mg) of 6-month duration was conducted. During each treatment period, concentrations of androgens, lipids, apolipoproteins, IGF-I, IGF-binding protein-1 (IGFBP-1), IGFBP-3, insulin sensitivity, percent body fat, libido, and sense of well-being were measured. A subgroup of men (n = 8) and women (n = 5) underwent 24-h sampling at 20-min intervals for GH determinations. DHEA and DS serum levels were restored to those found in young adults within 2 weeks of DHEA replacement and were sustained throughout the 3 months of the study. A 2-fold increase in serum levels of androgens (androstenedione, testosterone, and dihydrotestosterone) was observed in women, with only a small rise in androstenedione in men. There was no change in circulating levels of sex hormone-binding globulin, estrone, or estradiol in either gender. High density lipoprotein levels declined slightly in women, with no other lipid changes noted for either gender. Insulin sensitivity and percent body fat were unaltered. Although mean 24-h GH and IGFBP-3 levels were unchanged, serum IGF-I levels increased significantly, and IGFBP-1 decreased significantly for both genders, suggesting an increased bioavailability of IGF-I to target tissues. This was associated with a remarkable increase in perceived physical and psychological well-being for both men (67%) and women (84%) and no change in libido. In conclusion, restoring DHEA and DS to young adult levels in men and women of advancing age induced an increase in the bioavailability of IGF-I, as reflected by an increase in IGF-I and a decrease in IGFBP-1 levels. These observations together with improvement of physical and psychological well-being in both genders and the absence of side-effects constitute the first demonstration of novel effects of DHEA replacement in age-advanced men and women.
It has been postulated that dehydroepiandrosterone (DHEA) and its sulfate ester, dehydroepiandrosterone sulfate (DHEAS), the major secretory products of the human adrenal gland, may be discriminators of life expectancy and aging. We examined the relation of base-line circulating DHEAS levels to subsequent 12-year mortality from any cause, from cardiovascular disease, and from ischemic heart disease in a population-based cohort of 242 men aged 50 to 79 years at the start of the study. Mean DHEAS levels decreased with age and were also significantly lower in men with a history of heart disease than in those without such a history. In men with no history of heart disease at base line, the age-adjusted relative risk associated with a DHEAS level below 140 micrograms per deciliter was 1.5 (P not significant) for death from any causes, 3.3 (P less than 0.05) for death from cardiovascular disease, and 3.2 (P less than 0.05) for death from ischemic heart disease. In multivariate analyses, an increase in DHEAS level of 100 micrograms per deciliter was associated with a 36 percent reduction in mortality from any causes (P less than 0.05) and a 48 percent reduction in mortality from cardiovascular disease (P less than 0.05), after adjustment for age, systolic blood pressure, serum cholesterol level, obesity, fasting plasma glucose level, cigarette smoking status, and personal history of heart disease. Our conclusions are limited by the single determination of DHEAS levels, but the data suggest that the DHEAS concentration is independently and inversely related to death from any cause and death from cardiovascular disease in men over age 50.
The functional integrity of the hypothalamic-pituitary-ovarian and hypothalamic-pituitary-adrenal axes was assessed by determining pulsatile LH, ACTH, and cortisol secretion during the early follicular phase in athletic women with regular menstrual cycles (CA; n = 9), athletic women with amenorrhea (AA; n = 9), and regularly cyclic sedentary women (CS; n = 8). The CA and AA women were not significantly different in body composition, exercise training, psychometric tests, or dietary consumption. The CA women had shorter luteal phases (P less than 0.05) and lower urinary excretion of pregnanediol glucuronide than the CS women. In the AA women, urinary estrone glucuronide, pregnanediol glucuronide, and LH excretion were low throughout a 30-day period. The CA women had a 24-h pattern of pulsatile LH secretion characterized by reduced frequency (P less than 0.05) and increased amplitude (P less than 0.05), yielding an overall increased 24-h mean level (P less than 0.05), but interpulse intervals similar to those in the CS women. During sleep, LH pulse frequency slowed in the CS and CA women, while pulse amplitude increased and the mean serum LH level decreased in both groups. The AA women had even fewer pulses (P less than 0.05) of normal amplitude occurring at much more variable (P less than 0.01) interpulse intervals. Sleep-associated changes in LH pulsatility were absent. Responses to a 10-microgram bolus GnRH dose revealed blunted (P less than 0.05) FSH release in CA and augmented (P less than 0.05) LH release in AA women. The groups did not differ in any 24-h ACTH pulse pattern parameter or in cortisol pulse frequencies. Yet, early morning (0200-0800 h) serum cortisol levels were higher (P less than 0.05) in both groups of athletes, and this elevation was extended through the day (0800-2000 h; P less than 0.001) and evening (2000-0200 h; P less than 0.05) in the AA women. The plasma ACTH and serum cortisol responses to bolus human CRH administration were blunted in the CA and AA women [change from baseline (delta) in ACTH, P less than 0.05 and P less than 0.01; delta cortisol, P less than 0.01 and P less than 0.01, respectively], but adrenal sensitivity (delta cortisol/delta ACTH ratio) was increased (P less than 0.05). The plasma ACTH and serum cortisol responses to meals also were blunted in the athletic groups (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
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