What evidence do you have for your claim that

Some cells do fundamentally alter their function in response to exogenous hormones

????

By which I mean not exogenous hormones generally like insulin, thyroid hormone, hepcidin or adrenalin. And not sex hormones taken by the sex in which they are most prevalent and who have the appropriate receptors for them in the right amount, as in the case of the estrogen & progesterone in hormonal BC meant for females, the hormones in HRT taken by women for menopause, or the hormone oxytocin (in synthetic form pitocin) sometimes given to women in labor.

Please provide the evidence that "cells fundamentally alter their function in response to exogenous hormones" that pertains specifically to the particular sex hormones predominant in one sex taken by the opposite sex in amounts meant to mimic the levels that occur naturally in the opposite sex in their prime reproductive years - namely exogenous T taken by females in high doses, and exogenous estrogen taken in high dose by males.

Also, most TIMs who take exogenous estrogen also use powerful T blockers. How can you be sure that the changes in cellular function you claim are a result of exogenous (sex) hormones isn't due to powerful steroid hormone blockers like Spironolactone?

Waiting with bated breath to find out all the ways that cells "fundamentally alter their functions" due to exogenous sex hormones. Remember, you didn't say cells cease, reduce, increase, speed up their normal functions, or that they might proliferate, grow or shrink - you said cells "fundamentally alter their functions."

As for your claim that

TIMs offer an opportunity to study the longer-term effects of HRT treatment than post-menopause cases can offer.

No they don't! HRT stands for "hormone replacement therapy." The HRT you are talking about was designed to replace the hormones that women's bodies naturally make, have the correct kind & amount of receptors for, and which female bodies have evolved to utilize in female-specific ways. When males take these hormones it's not "HRT"! Moreover, you seem to be suggesting that post-menopausal women are physically the same as men. That's misogynistic, male-centrist, male-supremacist tosh.

Studying TIMs who take cross-sex hormones late in life will provide absolutely ZERO information - useful or not - about "the longer-term effects of HRT treatment." To get a picture "the longer-term effects of HRT treatment" requires studying women on long-term HRT. Not effing men.

As a matter of fact, quite a lot of research on "the longer-term effects on HRT" in women has been done, and more is ongoing. Why on earth would anyone think a good way - or the best way - to find out the impact of long-term HRT in us is to give female hormones to men and to study them?