In db/db mice, peripheral clearance of glucose was strongly reduced, whereas hepatic clearance of glucose by glucokinase was hardly affected compared to lean mice (5.1±0.7 ml.kg−1.min−1 vs. 4.6±0.7 ml.kg−1.min−1, lean vs. db/db mice, data not shown in the results section), the observed increase in glucose cycling is most likely driven by the extreme hyperglycemia in db/db mice. The gene discussed is GCK; the disease is Hyperglycemia.