Dr. Douglas Melton, who discovered the hormone betatrophin, has done tests on mice that were modified to be diabetic (raised on high-fat diets or genetically modified to show diabetic symptoms) and observed promising results.

I am currently writing a paper on a possibility of comparing the effects of betatrophin in obese diabetic mice vs. non-obese diabetic mice.

Aside from gender, size, weight, and diet (these are currently the most important ones that I have thought of) what other factors must be considered in order to perform a successful experiment?