DHT is widely said to be an estrogen antagonist, so from that perspective blocking DHT can increase estrogen. I have read that SP is also an estrogen antagonist, but it is rarely mentioned and it appears (to me) that this is only a minor effect of SP compared to its effect of blocking DHT and thus increasing estrogen. In the end the net effect of SP seems to be to increase estrogen.
Also, estradiol is produced in part from testosterone. So when you use SP to block testosterone conversion to DHT, testosterone levels rise (because T is not being converted). So, from this perspective also, using SP to block DHT raises estrogen (only estradiol) levels.
See this chart :
http://www.keratin.com/az/androgenestrogenmetabolism1.gif
The quote below is from
http://www.bodybuilding.com/fun/reform8.htm
"How does DHT protect against estrogen? There are at least three ways that this likely occurs. First of all, DHT directly inhibits estrogens activity on tissues. It either does this by acting as a competitive antagonist to the estrogen receptor or by decreasing estrogen-induced RNA transcription at a point subsequent to estrogen receptor binding.
"Second of all, DHT and its metabolites have been shown to directly block the production of estrogens from androgens by inhibiting the activity of the aromatase enzyme. The studies done in breast tissue showed that DHT, androsterone, and 5alpha-androstandione are potent inhibitors of the formation of estrone from androstenedione. 5alpha-androstandione was shown to be the most potent, while androsterone was the least.
"Lastly, DHT acts on the hypothalamus/pituitary to decrease the secretion of gonadotropins. By decreasing the secretion of gonadotropins you decrease the production of the raw materials for estrogen production testosterone and androstenedione (DHT itself cannot aromatize into estrogens). This property of DHT comes into particular utility when it is administered exogenously, and this is to be discussed in further detail in the next section."
Also, estradiol is produced in part from testosterone. So when you use SP to block testosterone conversion to DHT, testosterone levels rise (because T is not being converted). So, from this perspective also, using SP to block DHT raises estrogen (only estradiol) levels.
See this chart :
http://www.keratin.com/az/androgenestrogenmetabolism1.gif
The quote below is from
http://www.bodybuilding.com/fun/reform8.htm
"How does DHT protect against estrogen? There are at least three ways that this likely occurs. First of all, DHT directly inhibits estrogens activity on tissues. It either does this by acting as a competitive antagonist to the estrogen receptor or by decreasing estrogen-induced RNA transcription at a point subsequent to estrogen receptor binding.
"Second of all, DHT and its metabolites have been shown to directly block the production of estrogens from androgens by inhibiting the activity of the aromatase enzyme. The studies done in breast tissue showed that DHT, androsterone, and 5alpha-androstandione are potent inhibitors of the formation of estrone from androstenedione. 5alpha-androstandione was shown to be the most potent, while androsterone was the least.
"Lastly, DHT acts on the hypothalamus/pituitary to decrease the secretion of gonadotropins. By decreasing the secretion of gonadotropins you decrease the production of the raw materials for estrogen production testosterone and androstenedione (DHT itself cannot aromatize into estrogens). This property of DHT comes into particular utility when it is administered exogenously, and this is to be discussed in further detail in the next section."