Diabetes, Vol 46, Issue 12 1958-1964, Copyright © 1997 by American Diabetes Association
Sensitization to insulin induced by beta,beta'-methyl-substituted hexadecanedioic acid (MEDICA 16) in obese Zucker rats in vivo
N Mayorek, B Kalderon, E Itach and J Bar-Tana
Department of Human Nutrition and Metabolism, Faculty of Medicine, The Hebrew University, Jerusalem, Israel.
Beta,beta'-methyl-substituted hexadecanedioic acid (MEDICA 16) consists of
a nonmetabolizable long-chain fatty acid designed to probe the effect
exerted by fatty acids on insulin sensitivity. The effect of MEDICA 16 was
evaluated in insulin-resistant Zucker (fa/fa) rats in terms of liver,
muscle, and adipose tissue response to clamped euglycemic hyperinsulinemia
in vivo. Nontreated Zucker rats were insulin resistant, maintaining basal
rates of total-body glucose disposal, glucose production in liver, free
fatty acid (FFA) flux into plasma, and FFA reesterification in adipose
tissue, irrespective of the insulin levels induced. MEDICA 16 treatment
resulted in an insulin-induced decrease in hepatic glucose production,
together with an insulin-induced increase in total-body glucose disposal.
Intracellular reesterification of lipolysed FFA in adipose tissue was
specifically activated by MEDICA 16, resulting in a pronounced decrease in
FFA release, with a concomitant decrease in plasma FFA. In conclusion,
MEDICA 16 treatment results in the sensitization of liver, muscle, and
adipose tissue to insulin in an animal model for obesity-induced insulin
resistance.