Black tea inhibits rat liver microsomal 5-AR-1, not 5AR2

[michael barry]

http://carcin.oxfordjournals.org/cgi/co ... /25/7/1109




"In this study, we examined whether 5GG and theaflavins have inhibitory effects on androgen production and action of prostate cancer. We used rat liver microsomes as 5-reductase enzyme source. Unlike human, only 5-R1 is detected in rat liver. We found that 5GG and theaflavins inhibit 5-R1 activities. "


Interesting stuff. I guess if you wanted to inhibit 5-alpha-reductaste type 1, you could drink a lot of strong black tea. Im dissapointed that type 2 alpha five wasn't inhibited by the black tea theafalvins and polyphenols, but thats what they found. Apparently when these cells get cancerous, the type 1 created-DHT is especially harmful to rodents. That doesn't seem to be that much help to humans interested in 5AR2 though. LOL

 

[n0142248]

From that paragraph i deduce that they didnt actually measure its inhibitory affect on type 2. They only measured type 1 reductase which they got from the liver. It could well be the case that it also inhibits type 2. Interesting..

 

[michael barry]

From that paragraph i deduce that they didnt actually measure its inhibitory affect on type 2. They only measured type 1 reductase which they got from the liver. It could well be the case that it also inhibits type 2. Interesting..

In the mice/green tea, black tea, soy experiments, black tea inhibited 72% of mouse DHT. I was hoping at the time that mice would have similar alpha five reductase distribution as humans do. It would seem that if black tea inhibited both isoforms of the enzyme, that nearly 100% would be inhibited.

One note in the article that was interesting was that human alpha five reductase and mouse alpha five reductase were a little different from each other:

There are two different isoforms of 5-reductase (5-R1 and 5-R2), which have been characterized in humans, monkeys, rats and mice, each encoded by different genes. The average sequence identity between isozymes within a given species is 47%, while the sequence identity between the same isozyme across species is 60% for 5-R1 and 77% for 5-R2 (11).