Possible Interaction: Dehydroepiandrosterone and Estrone

“CONCLUSION(S) Administration of low doses (25 mg) of DH A po sitively modulates several endocrine parameters in early and late postmenopausal women, inducing the increase of the androgenic, est rogenic, a nd progestogenic milieu and reducing the climateric symptoms, similarly to estroprogestin replacement therapy.”

“Clinical studies carried out in small groups of subjects have clearly demonstrated that the administration of DHEA to the elderly increases many hormone levels, including that of insulin-like growth factor-1, (free and total) testosterone, dihydrotestosterone, oestrone and oestradiol.”

“However, DHEA regimen is also associated with an increased estrogenic availability.”

“Moreover, DHEA administration enhanced serum levels of DHEA, DHEAS, testosterone, and estrone , and regression analyses demonstrated that levels of DHEA and its metabolites were positively related to cognitive performance on the visual-spatial tasks in the DHEA condition.”

“RESULTS DH A tr eatment with exercise resulted in increases in circulating sulfated DHEA (650%), total testosterone (100%), estradiol (165%), est rone (8 5%), and IGF-I (30%) (all P < or = 0.05, for all within and between treatment comparisons).”

“The K(m) of estrone is more than 1000-fold lower than that of DHEA and the K(m) of estradiol is about 10 times lower than that of DHT.”

“A significant correlation between formation of estrone and dehydroepiandrosterone occurred for all cell lines (r = 0.98, P less than 0.001) indicating that the same 17 beta-hydroxysteroid dehydrogenase was probably involved.”

“ Dehydroepiandrosterone had only 1% the inhibitory activity of estrone.”

“Equimolar concentrations of dehydroepiandrosterone, estrone or estradiol cause significant inhibition (to 50%) of this activity but dehydroepiandrosterone sulfate and estriol did not.”

“For example, estrone and estradiol-17 beta inhibit the oxidation of both substrates competitively with Ki values of between 15 and 24nM. The Km values of dehydroepiandrosterone and pregnenolone with NADP+ as cofactor are higher than those with NAD+ as cofactor and the V values are much lower.”