Possible Interaction: Progesterone and Dihydrotestosterone

“The primary effect is the abolition … action of phenolic estrogens and progesterone … dihydrotestosterone is administered concurrently, presumably through direct action at the tumor cell level A secondary contributory suppressive effect is the depression of ovarian activity, and consequently of the production of phenolic estrogens and progesterone, by these compounds.”

“ Progesterone , at the level of the hair follicle, decreases the conversion of testosterone into DHT.”

“As a consequence of … important observation that progesterone and deoxycortisone inhibits the synthesis of DHT by competing with 4-en-3-one function of the testosterone for the 5alpha-reductase enzyme a number of pregnane derivatives were synthesized and have been reported as inhibitors of human 5alpha-reductase enzyme.”

“Oestrogens and androgens stimulate collagen matrix synthesis, while progesterone is a competitive inhibitor for the 5 alpha-reduction of testosterone to 5 alpha-dihydrotestosterone (DHT).”

“ Progesterone inhibited DHT synthesis in HGF from 14C-testosterone by 24-62% (n = 8; p < 0.01).”

“ Progesterone inhibited the formation of DHT and 4-A by 10-fold and 3-5-fold at effective inhibitory concentrations (n=4; p<0.001), when 14C- testosterone was used as substrate.”

“In genital skin fibroblasts, a 3 to … h of treatment of the cultures with dihydrotestosterone (DHT, 5 nM) whereas a 22 fold decrease is observed … increase is also observed after 1 h of treatment with progesterone (50 nM) or cyproterone acetate (500 nM) … as an antiandrogen in this model.”

“ Dihydrotestosterone also inhibited progesterone production, but to a lesser extent than testosterone.”

“The nonaromatizable androgen 5 alpha-dihydrotestosterone also inhibited progesterone production, but by no more than 45-50% even at supraphysiological concentrations.”

“An inhibition of testosterone 5α-reduction to dihydrotestosterone was also observed after this percutaneous administration of progesterone.”

“The transformation of radioactive testosterone to dihydrotestosterone was inhibited by this in vitro addition of progesterone.”

“ DHT and T induced a concentration-dependent upregulation of Hsd3b and CYP11 expression, as well as increased progesterone concentrations in spent media.”