Quote from: KayXo on July 15, 2014, 10:22:17 AMI don't think androgens decrease SHBG. They just do nothing whereas estrogen in the liver stimulates production of SHBG.
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.
Quote from: KayXo on July 15, 2014, 10:22:17 AMProgesterone reduces and replaces Testosterone.
This interested me because basically of what I mentioned before of higher androgen levels being present and more noticeable feminization progress being present. Whenever I've mentioned progesterone increasing breast growth, even on here, the consensus has always been mixed. Dutch studies have found it has no direct impact, while Boston US swears by progesterone in their patients. If progesterone does replace testosterone then perhaps this is reducing SHBG levels, allowing more active estrogen, and increasing breadth growth in that way.
I 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, only estrogen, so they assumed progesterone must play no role in breast development. If there were evidence of progesterone helping breast development we would've heard about it already. There is so much breast growth supplements BS out there that this would've been discovered long ago if it were true. However 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.
Personally most endocrinologists I've worked with seem to think transgendered HRT is simply getting our estrogen and testosterone levels within genetic female levels and hoping by some odd luck we feminize. None of my endocrinologists have ever cared enough to think about any of this, I've had to direct my healthcare in this regard, and I doubt I'm the first. Like I suspected HRT can't be that simple. While we live as females, we still have genetic male endocrine systems, probably not designed to work well with genetic female levels. Remember 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.