Depends on where you live. If it were me, I'd start with doctors who are actively involved with Joslin, or with a research-oriented teaching hospital like Mass. General.
If you don't live close to a city with one of those, I'm not sure what your best options would be.
If it's a huge deal, you might consider establishing a relationship with a specialist who you have to travel a long distance to visit, or even consider relocating.
EDIT: It's also been my experience that the occasional clinical endocrinologist NOT affiliated with a research / teaching hospital stays on top of current research. If your GP has been in working locally for a while, he/she may know which local endocrinologists are the sharpest, and may trust you well enough to make a few recommendations.
Also, I'm not sure if this is just an anomaly, but I've found that the local endocrinologists who immigrated from Poland are really on top of things.
How do you even go about finding a doctor who "stays abreast of this kind of research" .