So it jams the receptor for sex hormones (all sex hormones or just some?) but not the receptors for growth hormones. That allows the child to keep growing in other ways.
Do gonads have receptors for hormones from the opposite sex? (edit: Yes, i guess yes) How many years on hormone cause a FTM to have to get a hysterectomy? What happens to their ova?
It jams up receptors for estrogen or testosterone. While the receptors for growth hormones wouldn't be affected directly, they are indirectly affected in that the amount of growth hormone secreted is supposed to happen in conjunction with various stages of puberty. The pituitary gland is involved in puberty and won't do puberty related jobs.
There are other pieces of the puzzle here, like follicle stimulating hormone (FSH) and luteinizing hormone (LH). The pituitary gland makes these compounds as a part of puberty. These hormones are absolutely required for males to make sperm and for a females eggs to become viable for ovulation. Without a natural start for puberty there isn't a reason for the body to manufacture them. I don't know if the body makes such hormones if you give cross sex hormones, but the gonads are ruined so it isn't like the hormones would do much anyway. I don't have the best memory about the order in which the hormonal cascade happens, the info is out there if you are feeling curious. It is supposed to unfold in a specific manner, no one has fucked with the process so badly until recently so the exact extent of the problems created isn't known. Females also naturally make progesterone as a part of the hormonal changes for menstruation. Missing out on that may have some kind of health consequence.
The usual recommendation for FTM hysterectomy is to spend no more than 5 years on testosterone. This guideline is guesswork. One of the pioneering ftms had their cervix fuse and uterus fill up with infection before getting an emergency hysterectomy (buck angel), and the 5 year thing seems to have become standard advice after that nearly killed buck. Other women with far less testosterone exposure have had problems with reproductive cancers. FTMs that discuss transition online have started to discuss uterine pain that comes on with orgasm, lasts several minutes, and increases in duration and intensity the longer they keep their uterus intact. It doesn't happen to everyone but it seems to be something that happens an unknown percentage of the time for long term testosterone users.
The ova of a girl who is puberty blocked and given testosterone simply never get the chance to mature. The egg will stay parked in the ovary forever as an immature egg while the ovary itself is atrophied by testosterone so the process cannot be reversed. Girls are born with all the eggs they will ever have, and many of them are destroyed through normal processes over a lifetime. There are so many extras as to be redundant, but more can never be made. Maybe something worse happens to the eggs like genetic damage, but science won't be able to report on it for quite awhile for various reasons. Surgeons that have removed their ovaries have described them as looking like shriveled raisins, which is markedly different from a healthy ovary.
Hormones are insanely complex chemicals and also have feedback systems within the body to modulate their output. Some hormone receptors exist only for that reason, to monitor circulating hormones and change output. Endocrinologists are the doctors that deal with the hormonal systems of the body, and usually their job is to bring hormones back into balance. Transgender patients are asking for a drug regimen that mimics a disease state. Its the opposite of medicine. All the sane endos seem to treat diabetes primarily.