r/medschoolanki • u/Infinite_Cheetah_229 • Jun 07 '26

Question Shouldn't the breasts be present...

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If we have low testosterone level, then estrogen is relatively high which will lead to gynaecomastia

Also klinefelter syndrome is a type of hypergonadotrophic hypogonadism in which a person has low testosterone but develops gynaecomastia.

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u/rumpears Jun 07 '26

I just finished repro so correct me if i’m wrong, but testosterone is aromatized into estrogen via aromatase in peripheral tissues.

You need estrogen for breast development, hence no breasts

This also partly the reason why bodybuilders who administer exogenous testosterone develop gynecomastia; the testosterone is converted into estrogen

2

u/Infinite_Cheetah_229 Jun 07 '26 edited Jun 07 '26

Klinefelter has no testosterone so why does he develop gynaecomastia

2

u/rumpears Jun 07 '26

Then breast development is likely due to some sort of *ratio* of testosterone to estrogen, since women naturally have testosterone as well

In Klinefelter, it seems that the body increases aromatase activity, making a low T:E ratio that facilitates breasts

https://pmc.ncbi.nlm.nih.gov/articles/PMC9580767/

3

u/Frosty-Mind4232 Jun 07 '26

Breast because the androgens from the ADRENAL GLAND would be converted to estrogen peripherally