Glycogen synthase activity in quad, gastroc and liver of GSK-3α muscle KO animals.

Glycogen synthase activity was determined in (A) quad, (B) gastroc and (C) liver of eight weeks old MLC Cre – (open bars) and MLC Cre + (filled bars) tissues by assaying incorporation of glucose from uridine diphospho-{6-³H)-D-glucose into glycogen and expressed as a ratio of activity in the absence divided by that in the presence of glucose-6-phosphate. Values are the mean ± SEM for at least five experiments carried out in duplicate. Glycogen content was measured in (D) quad, (E) gastroc and (F) liver from eight week old MLC Cre − (open bars) and MLC Cre + (filled bars) following either an overnight fast or random feeding. Tissues were extracted, acid-hydrolyzed and glycosyl units assayed using a glucose reagent hexokinase method (Amresco, Ohio) as described in Experimental Procedures. Glycogen content is expressed as µmol glucose/g tissue. Values are mean ± SEM from at least five separate animals with each assayed in triplicate. Genetic background of the animals was C57BL/6/129.