Effect of odd and even numbered medium chain fatty acids on glucose uptake by adipose tissue.

Abstract

The effect of odd and even numbered medium chain fatty acids (MCFA) on glucose uptake by rat adipose tissue was studied in vitro, in the absence and presence of varying concentrations of insulin. The MC FA studied were octanoate (C8), nonanoate (C9), and decanoate (C10), and a three-carbon fatty acid, propionate. The effect of the odd numbered fatty acid, nonanoate, differed strikingly from that of an equimolar amount of the even homologues. The presence of nonanoate in the incubation medium was associated with a significant increase in glucose uptake with and without insulin, while octanoate, decanoate, and propionate exerted no such enhancing effect on glucose uptake. Incubation studies of adipose tissue with varying amounts of nonanoate indicate that the glucose uptake varied directly with the concentration of the fatty acid in the medium. Enhanced glucose uptake in the presence of nonanoate is not likely to be related to the glucogenic potential of the propionate moiety of the odd numbered fatty acid and has been ascribed to possible increased incorporation of this fatty acid into triglyceride of adipose tissue.