GCK and diabetes mellitus: Similar to our results, previous research showedthat Gck expression was higher in ZDF rats at age10–11 weeks comparedto their lean counterparts, and there was no difference in the glucokinaseprotein level between ZDF rats and lean Zucker rats.44 However, as diabetes progressed in the ZDF rats (from 14to 28 week of age), both Gck and glucokinase proteinlevels were decreased.44 NAAB increased Gck expression indicating its potential role as a glucokinaseactivator.