Protocols for the liver glycogen extraction (Clow et al., 2004) and assay were modified from Bergmeyer et al. (1974). Hydrolysates were frozen at −80°C until analyzed for glucose content. The glucose assay was modified to use 25 µl of sample, diluted 1:7 in assay media (Clow et al., 2004) and added to each well of a microtiter plate. Twenty-five microlitres of 100 µl/ml G-6-PDH was added to each well to eliminate any endogenous G-6-P that remained in solution. The plate was read on a VERSAmax Tunable Microplate Reader (Molecular Devices Corporation) at 340 nm until absorbance stabilized. Hexokinase (25 µl) was then added and the absorbance was read after 15–25 min.