Extremely fascinating potential regulatory mechanism of the HPTA, and the possibility

that estrogen is what is responsible for male brain development.

Something that has bugged me for a while is Dr Saya's case study, how could it be possible that giving exogenous estradiol could increase testosterone levels?

http://defymedical.com/resources/he...-hpta-suppression-for-mtf-transgender-patient

I may have found an answer, and Dr Saya I'd absolutely love it if you could comment on the likelihood of this potential mechanism.

The lower the estrogen-convertible androgen or primary estrogen level during brain differentiation, the higher the evocability of a positive estrogen action on LH secretion in later life

In addition, the evocability of a positive estrogen feedback was also demonstrable in most homosexual male-to-female transsexuals in significant contrast to hetero-or bisexual male-to-female transsexuals.

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johndoesmith said:

that estrogen is what is responsible for male brain development.

Something that has bugged me for a while is Dr Saya's case study, how could it be possible that giving exogenous estradiol could increase testosterone levels?

http://defymedical.com/resources/he...-hpta-suppression-for-mtf-transgender-patient

I may have found an answer, and Dr Saya I'd absolutely love it if you could comment on the likelihood of this potential mechanism.

Click to expand...

Agree that sounds fascinating and also agree it may present a possible mechanism.

Dr Justin Saya said:

Agree that sounds fascinating and also agree it may present a possible mechanism.

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I was literally just thinking about this thread Haha perfect timing!

Any comments or input you have?

Nothing to add other than good job digging. I've never heard of that proposed mechanism, you should post the reference if you still have it. Very interesting as a possible novel mechanism.

Dr Justin Saya said:

Nothing to add other than good job digging. I've never heard of that proposed mechanism, you should post the reference if you still have it. Very interesting as a possible novel mechanism.

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Whoops. Completely forgot to cite this.

Since 1964, we have found positive estrogen feedback to be a relatively sex-specific reaction of the hypothalamo-hypophyseal system in rats as well as in human beings. It is dependent on the estrogen-convertible androgen level during sexual brain differentiation and also on estrogen priming in adulthood. The lower the estrogen-convertible androgen or primary estrogen level during brain differentiation, the higher the evocability of a positive estrogen action on LH secretion in later life. In clinical studies, we induced a positive estrogen feedback luteinizing hormone secretion in most intact homosexual men, in clear-cut contrast to intact heterosexual or bisexual men. In addition, the evocability of a positive estrogen feedback was also demonstrable in most homosexual male-to-female transsexuals in significant contrast to hetero-or bisexual male-to-female transsexuals. The following relations have been found between sex hormone levels during brain differentiation and sex-specific responses in adulthood: (i) Estrogens, which are mostly converted from androgens, are responsible for the sex-specific organization of gonadotropin secretion and hence the evocability of a positive estrogen feedback in later life; (ii) both estrogens and androgens, occurring during brain differentiation, predetermine sexual orientation, and (iii) androgens, without conversion to estrogens, are responsible for the sex-specific organization of gender role behavior. Furthermore, the organization periods for sex-specific gonadotropin secretion, sexual orientation, and gender role behavior are not identical but overlapping. Thus, combinations as well as dissociations between deviation of the neuroendocrine organization of sex-specific gonadotropin secretion, sexual orientation, and gender role behavior may occur.

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https://www.ncbi.nlm.nih.gov/pubmed/3282489

Accordingly, the intrinsic pattern of mammalian brain development is female, and estrogen is required for the development of a male brain

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http://www.endotext.org/chapter/estrogens-and-male-reproduction/

Although you'll need to create a login but it is probably one of the most valuable texts I've found, and it's in rather advanced language, which I like.

The fact that congenital aromatase deficiency does not affect psychosexual orientation and gender-identity in humans suggests that estrogens do not mediate the organizational effects on male sexuality induced by early exposure to androgens

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This is mentioned after the second quote, referring to male brain development being dependant upon having intact aromatase enzyme in utero. I do wonder if aromatase deficient men are influenced by estradiol that crosses the placenta in utero, essentially invalidating the use of aromatase deficient men as a "control".

That's where my knowledge comes to a halt, and your medical school will come in handy. It's a lot to digest but I'd be grateful if you commented on this aspect most.

Figured this got a lot of views but not a lot of replies that people are interested in this.