ABSTRACT
BACKGROUND: DHEA-S is the most abundant steroid hormone in circulation, and primarily secreted from the adrenal cortex, but its physiological role is little known. One of the characteristic features of DHEA-S is progressive decrement of plasma DHEA-S level with advancing age, in contrast, plasma levels of other adrenal hormones are not chaging or littie decreasing. To grasp the trends of plasma DHEA-S level and DHEA-S/cortisol ratio by age in healthy Korean, we measured the plasma DHEA-S levels and DHEA-S/cortisol ratios in healthy Korean. METHODS: Healthy Korean (men: 99, women: 102, age range: 15-97 year old)were studied. Subjects were not taking drugs (such as glucocorticoid or androgenic medication) or cigarettes known to modify the plasma level of DHEA-S and cortisol, and had no evidence of hepatic, renal disease or hyperlipidemia as determined by serum lipid, bilirubin, SGOT, SGPT, BUN, creatinine. Data were analyzed by 10-year age group for men and women: i.e, 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, 80-89 and 90 year or more. Plasma DHEA-S levels were measured by using a commercially available RIA kit with 125I labeled-DHEA-SO4 (Coat-A Count DHEA-SO4), and for the measurement of plasma cortisol levels, commercial Gamma Coat TM[125I] Cortisol Radioimmunassay Kit was used. RESULTS:. 1) In both men and women, plasma DHEA-S level showed high interindividual variation within the same age group. 2) There were individual sex differences in plasma levels of DHEA-S, in all age groups, plasma DHEA-S levels were significantly higher values for men than for women. 3) Maximum plasma DHEA-S levels (men; 237+-3.35 ug/dL, women; 108+-17.5 ug/dL) were at third decade in both men and women. 4) Both men and women showed the continuous decline in plasma DHEA-S level with age. These age-related decline was more prominent in men than in women (men; y=-3.152 * +292.6, r2= 0.8459, P<0.05, women; y= -1.417 * +143.3, r2 = 0.7278, P< 0.05). 5) As an index of aging, there was no stastical difference between DHEA-S and DHEA-S/cortisol ratio. CONCLUSION: In healthy Korean, there were high interindividual variation of plasrna DHEA-S levels. In both men and women plasma DHEA-S level was peak at third decade, and from when it declined progressively with age. These results suggest that although the reliability of single plasma DHEA-S measurement are limited, the decline of DHEA-S with advancing age might be a specific marker of endocrinologic hormonal milieu (aging index). Also, concerning to individual adrenal secreting capacity, we measured DHEA-S/cortisol ratio. But we did not found that plasma DHEA-S/cortisol ratio is superior to the plasma DHEA-S level as an aging index.