|Image 1: Otsuka Long-Evans Tokushima fatty rats (OLETF, right) have the genetical disposition to become type II diabetics.|
Biotin could help even if "it's in your genes" ;-)
The Japanese researchers used the infamous Otsuka Long-Evans Tokushima fatty rats whose name already implies that their have the unfortunate propensity to gain tons of body fat and develop type II diabetes, even if they are not fed the "high fat" diet (of which at least those of you who are not the first time here at the SuppVersity should know by now that it is high in fat and carbs) to check, whether supplementation could ameliorate the inevitable development of skeletal muscle insulin resistance in these poor critters.
|Figure 1: Body weight, fasting glucose and insulin levels at the beginning and end of the 8-week study period (data adapted from Sasaki. 2012)|
|Figure 2: Glucose uptake, total and membrane GLUT-4 expression in hindlimb muscle of 42-week old OLETF rats with or without biotin treatment (data calculated based on Sasaki. 2012 and expressed relative to non-diabetic LETO control)|
Biotin does not via AMPK... good or bad news?
These observations lead the scientists to conclude that the mechanism that is responsible for the nevertheless beneficial effects of supplemental biotin can not be a direct consequence of AMPK activation, which is at the heart of both exercise, as well as drug (esp. Metformin) induced ameliorations in insulin sensitivity. This is something, I actually find pretty interesting, because a) the elucidation of the exact mechanism by which biotin is able to increase insulin sensitivity and skeletal muscle glucose uptake could lead to novel insights into skeletal muscle glucose metabolism which could also be of relevance for "physical culturists", and b) if biotin, despite being essential for the activation of Acetyl-CoA carboxylase (ACC), a major downstream target of AMPK, does not work by "simply" stimulating the AMPK pathway, it is actually likely that the effects of biotin supplementation and exercise could add up.