when is insulin not insulin ?
so what your saying is that metformin DOES NOT promote insulin sensitivity ?
Lets see.....
most of the insulins prescribed now days (humalog, novolog, lantis) are not "insulin". It used to be diabetics were treated with actual "insulin" by injecting bovine or pork insulin. These insulins are nearly identical to human insulin, differing by only a couple of amino acids each (pork is 1 or 2, bovine is 3). This stopped with the DNA recombinant technolgies in the 1980s. At that time, humulin R was developed which is a DNA recombinant technology "Human" insulin. From there the technology moved to insulin analogues which are chemical structures similar to insulin which act on the insulin receptor, but really aren't insulin chemically. They are an altered form, unlike anything occuring naturally in nature, but still have an insulin action.
And for the second question,
No, I'm saying its not known to the best of my knowledge.