Quote from: teeg on July 16, 2014, 07:35:25 PM
SHBG is decreased naturally by androgens (as well as other hormones), and especially by anabolic steroids. I saw a thread on a body building forum talking about ways to reduce SHBG as it binds all sex hormones, reducing available testosterone, and thusly reducing "gains". One of the reason steroids work so well is not only because of the influx of androgens, but steroids are almost always cycled with GH, which greatly lowers SHBG, allowing more free testosterone.
I've never come across information suggesting that anything including androgens (or progesterone, as you suggest later) REDUCE SHBG. Can you cite actual studies, medical texts, etc that state this and have shown this for certain?
Quote from: teegI once saw a study where some British endocrinologist (she was FTM I think) discussed progesterone not being present during puberty where the majority of breast development occurs
During puberty, a girl eventually bleeds and goes through menstrual cycles where progesterone rises during the second half of the cycle. Progesterone is clearly present during puberty, not always present in significant amounts but here and there. At first though, only estrogen is present.
Quote from: teegIf there were evidence of progesterone helping breast development we would've heard about it already.
And we have. Plenty! I, for one, have experienced increased breast growth on P. Others on this forum have as well. There are plenty of studies showing the important role of P in breast development for lobulo alveolar growth and showing that density of breasts is highest when P increases (during the luteal phase) compared to E alone (follicular). Also, a VERY common "complaint" of women going on progesterone (and progestins) is swollen breasts!!!
Quote from: teegHowever what this endocrinologist didn't mention is that SHBG levels drop by half when females enter puberty allowing sex hormones activity to greatly increase and mature the body.
SHBG actually increases in females due to the action of estrogen. If you compare SHBG levels in females vs males during puberty, they are higher in females.
Quote from: teegWhile we live as females, we still have genetic male endocrine systems, probably not designed to work well with genetic female levels.
I disagree. I am doing quite well right now on genetic female levels since they range from less than 100 to up to 75,000 pg/ml. Many transgirls do quite well too. I very much doubt that being XY does anything detrimental. If anything, it's that we started late taking hormones so that our bodies already masculinized some or too much and that when we do take hormones, our GROWTH hormone levels are quite low compared to during puberty which could affect breast growth, for example. I think that if an XY male (like those with androgen insensitivity) started female hormones when they were 10-12 yrs old, results would be just as good for them as for any natal female, of course, depending on their genetics too and how much they would be given.
Quote from: teegRemember that there's still little to no research on most any of the treatment we undergo. Research on breast cancer for MTF patients, progesterone effects for MTF patients, etc., there is little to none.
Not extensive research, indeed but if you really search through the studies, you'll find quite a few. It
appears (although more research is needed) that breast cancer is quite rare in transwomen. Harry Benjamin had stated to have found none in his patients as well as Gooren in Amsterdam whose team followed hundreds, if not thousands of transwomen throughout several decades although I think he found one or two later. I think only a few cases have been reported in the literature but who knows if there were more unreported. His team also published a study where they said that progestative substances did seem to make a difference in terms of breast growth and another team from Canada also remarked that it was used to allow breast to fully mature. Etc...if you look, you will find some interesting stuff. More is needed though, I agree.

But, still with that information alone and that of ciswomen and studies on prostate cancer patients, we start to get a better idea.