I know, this thread has been exhausted (kind of a mixed metaphor), and I try
not to send gratuitous personal anecdotes unless they're of general interest.
I think this may be.  My daughter was 10 when she was diagnosed with diabetes.
She had evidently lost some weight (one of the classic symptoms), because as
soon as she got on insulin she almost immediately gained 10 lbs.  Shortly
thereafter, she developed breast buds.  This seems to me an example of a
threshold of body fat below which hormonal function is suppressed, or at least
reduced.  Somewhat like women with anorexia or extremely active athletes who
stop getting periods.  Some relationship to differences in lactational
amenorrhea, perhaps?   Miriam Levitt RN, IBCLC, a Lactnut who sees connections
to breastfeeding everywhere!