Although the thing about a uterus transplant is that once you've had all the babies you want, you can remove it. It's not like it serves any other purpose. Then you can go off your meds.
Ooops. Seems you're right. The adrenal glands and fat tissue can produce estrogen. It's about 1/3 to 1/5 of pre-menopausal levels (30 ng/l). I knew about the fat tissue. Why didn't I think of that? (Fatty tissue can convert testosterone into estrogen, although the activity is very low.)