Sidebar to the Crossdreamers.com blog post "Does the effects of hormones on transgender prove that crossdreaming has a biological component?"
The complexity of the effects sex hormones have on our minds and bodies is mind-blowing, and can be hard to grasp.
On this page I have gathered a few quotes from medical experts that might be of help.
Estrogen refers to feminizing hormones, and includes estradiol. Androgens refers to masculinizing hormones, including testosterone.
Note that hormone therapy is not a simple "adding more A" or "adding more E" to the body. Instead you add hormones that interfere with some rather complex feedback loops of hormone production in the mind/body-system.
You may, for instance, help your body transform your own testosterone into estrogen. You may also influence the way your brain absorbs and make use of sex hormones (i.e. influence hormone reception as opposed to hormone production). If the brain stops processing a hormone, it does not matter how much of it you find in your blood stream.
Male or female hormone replacement therapy
Here is an extract from Thomas E. Bevan presentation in the book The Psychobiology of Transsexualism and Transgenderism:
"Oral estradiol [estrogen] blocks release of hypothalamic gonadotropin-releasing hormone (GnRH) that normally stimulates release of testosterone through other hormones. Release of GnRH in the hypothalamus causes the release of luteinizing and follicle-stimulating hormones in the pituitary. This, in turn, triggers synthesis and release of testosterone from the testes. Excessive testosterone feeds back on the GnRH mechanism in the hypothalamus and reduces the testosterone level. The GnRH feedback mechanism responds, not only to testosterone but also estradiol and progesterone.
Estradiol feminizes the body and stimulates growth of stromal tissue in the breast that determines breast structure. Combined with progesterone, estradiol also develops a second type of tissue, the lobular tissue of the breast, which is the actual milk-secreting tissue. In HT [hormone replacement therapy], the dosage of oral estradiol should be minimized because the most severe adverse side effects of MTF HT are believed to result from estrogens (...). Estrogen also increases the level of sex hormone-binding globulin (SHBG), which binds to testosterone and inactivates it. Estrogen also seems to maintain sexual interest even when testosterone levels are minimized (...).
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| Illustration: designer491 |
The complexity of the effects sex hormones have on our minds and bodies is mind-blowing, and can be hard to grasp.
On this page I have gathered a few quotes from medical experts that might be of help.
Estrogen refers to feminizing hormones, and includes estradiol. Androgens refers to masculinizing hormones, including testosterone.
Note that hormone therapy is not a simple "adding more A" or "adding more E" to the body. Instead you add hormones that interfere with some rather complex feedback loops of hormone production in the mind/body-system.
You may, for instance, help your body transform your own testosterone into estrogen. You may also influence the way your brain absorbs and make use of sex hormones (i.e. influence hormone reception as opposed to hormone production). If the brain stops processing a hormone, it does not matter how much of it you find in your blood stream.
Male or female hormone replacement therapy
Here is an extract from Thomas E. Bevan presentation in the book The Psychobiology of Transsexualism and Transgenderism:
"Oral estradiol [estrogen] blocks release of hypothalamic gonadotropin-releasing hormone (GnRH) that normally stimulates release of testosterone through other hormones. Release of GnRH in the hypothalamus causes the release of luteinizing and follicle-stimulating hormones in the pituitary. This, in turn, triggers synthesis and release of testosterone from the testes. Excessive testosterone feeds back on the GnRH mechanism in the hypothalamus and reduces the testosterone level. The GnRH feedback mechanism responds, not only to testosterone but also estradiol and progesterone.
Estradiol feminizes the body and stimulates growth of stromal tissue in the breast that determines breast structure. Combined with progesterone, estradiol also develops a second type of tissue, the lobular tissue of the breast, which is the actual milk-secreting tissue. In HT [hormone replacement therapy], the dosage of oral estradiol should be minimized because the most severe adverse side effects of MTF HT are believed to result from estrogens (...). Estrogen also increases the level of sex hormone-binding globulin (SHBG), which binds to testosterone and inactivates it. Estrogen also seems to maintain sexual interest even when testosterone levels are minimized (...).
Testosterone blocking agents [antiandrogens] are usually used to minimize the dosage of estradiol needed. Spironolactone blocks both testosterone release and blocks testosterone receptors that transmit messages to body cells. However, spironolactone is also an antihypertensive and potassium-sparing drug that results in lower blood pressure. For this reason, blood pressure and potassium levels should be monitored if it is prescribed. Spironolactone also reduces libido and arrests male pattern baldness. (...)"
If you are confused about the feedback loops of this system, the following presentation by Brooklyn Urology may be of help:
"The Anterior Pituitary (AP) releases 2 hormones known as Leutinizing Hormone (LH) and Follicle Stimulating Hormone (FSH), which are under regulation by the Hypothalamus, a section in the brain, that releases Gonadotropin Releasing Hormone (GnRH).
GnRH travels through very small vessels in the brain until it reaches the AP which in turns regulates the release of LH and FSH, both of which travel through the blood stream until they reach their designated target, the TESTIS (or Ovaries)!
LH is the hormone that tells cells in the testicle to produce Testosterone (Estrogen in the ovary) while FSH is in charge of sperm (follicle) production in the Testis (Ovary). After Testosterone is secreted into circulation, it can also self regulate itself. Too much T and it will send a signal to Slow down both the Hypothalamus and AP."
GnRH travels through very small vessels in the brain until it reaches the AP which in turns regulates the release of LH and FSH, both of which travel through the blood stream until they reach their designated target, the TESTIS (or Ovaries)!
LH is the hormone that tells cells in the testicle to produce Testosterone (Estrogen in the ovary) while FSH is in charge of sperm (follicle) production in the Testis (Ovary). After Testosterone is secreted into circulation, it can also self regulate itself. Too much T and it will send a signal to Slow down both the Hypothalamus and AP."
Marshall Dahl and his coauthors write:
"Endocrinologic feminization [hormone replacement therapy for male to female transgender] is achieved by (a) direct or indirect suppression of the effects of androgens, and (b) induction of female physical characteristics.
Androgen suppression can be achieved by:
Estrogen is the principal agent used to induce female characteristics, and works primarily by direct stimulation of receptors in target tissues.Although estrogen also suppresses luteinizing hormone (LH), the estrogen dose required for effective LH suppression is dangerously high."
"Endocrinologic feminization [hormone replacement therapy for male to female transgender] is achieved by (a) direct or indirect suppression of the effects of androgens, and (b) induction of female physical characteristics.
Androgen suppression can be achieved by:
- agents that suppress the production of gonadotrophic releasing hormone (GNRH) or are GNRH antagonists: e.g., progestational agents
- suppressing the production of luteinizing hormone: e.g., progestational agents, cyproterone acetate
- interfering with the production of testosterone or metabolism of testosterone to dihydrotestosterone (DHT): e.g., spironolactone, finasteride, cyproterone acetate
- interfering with the binding of androgens to receptors in target tissues: e.g., spironolactone, cyproterone acetate, flutamide
Estrogen is the principal agent used to induce female characteristics, and works primarily by direct stimulation of receptors in target tissues.Although estrogen also suppresses luteinizing hormone (LH), the estrogen dose required for effective LH suppression is dangerously high."
Female to male hormone replacement therapy.
Marshall Dahl and his coauthors write:
"Endocrinologic masculinization is achieved by the use of testosterone to induce male physical
characteristics. Testosterone works primarily by direct stimulation of receptors in target tissues;
clinical effects correlate to elevation of serum testosterone level to a male reference range, rather
than a decrease in serum estradiol. Testosterone also has antigonadotropic action in high doses."
Marshall Dahl et al: Endocrine Therapy for Transgender Adults in British Columbia:
Suggested Guidelines , Vancouver 2006.
Thomas E. Bevan: The Psychobiology of Transsexualism and Transgenderism, Preaeger 2015,
