title: Mechanism of action of anti-aging DHEA-S and the replacement of DHEA-S.
abstract: The plasma ACTH and cortisol levels do not change during aging. On the other hand, the plasma dehydroepiandrosterone sulfate (DHEA-S) changes remarkably during aging. Before puberty, the plasma DHEA-S level both in males and females is very low, however, it rapidly increases at puberty, and thereafter significantly decreases both linearly and age-dependently. Cytochrome P450c17 has two enzyme activities, 17-alpha-hydroxylase and 17,20-lyase. Cortisol is synthesized by 17-alpha-hydroxylase, and DHEA is synthesized by 17,20-lyase. The mechanism of dissociation of cortisol and DHEA synthesis in aging depends on another regulator of 17,20-lyase of cytochrome P450c17 such as cytochrome P450 reductase. We demonstrated significant decrease in cytochrome P450 reductase activity in bovine aged adrenal glands. We clarified the beneficial effects of DHEA as an anti-aging steroid based on both in vitro and in vivo experiments, such as the stimulatory effect of immune system, anti-diabetes mellitus, anti-atherosclerosis, anti-dementia (neurosteroid), anti-obesity and anti-osteoporosis. It is very important to identify the mechanism of action of DHEA. We clarified the conversion of DHEA to estrone by cytochrome P450 aromatase in primary cultured human osteoblasts. We indentified high affinity of DHEA binding with K(d)=6.6 nM in antigen and DHEA stimulated human T lymphocytes. We searched for the target genes that are specifically induced in activated T lymphocytes in the presence of DHEA by subtractive hybridization screening for differentially expressed transcripts. The double blind, randomized human replacement therapies utilizing DHEA are also reviewed.
authors.affiliation: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku,Fukuoka 812-8582, Japan. nawata@intmed3.med.kyushu-u.ac.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Nawata
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yanase
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Goto
authors.forename: Taijiro
authors.initials: T
authors.lastname: Okabe
authors.forename: Kenji
authors.initials: K
authors.lastname: Ashida
mesh_terms: D000375:Aging / Q000378:metabolism*; D003687:Dehydroepiandrosterone / Q000378:metabolism; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism*; D020249:Hormone Replacement Therapy; D006801:Humans
chemical_list: D003687:Dehydroepiandrosterone; D019314:Dehydroepiandrosterone Sulfate