Figure 4.

Rapid changes in glucose consumption. (A) Glycogen was depleted from HepG2 by initial perfusion with 0 mM glucose. The extracellular glucose was then increased to 10 mM for 35 min with insulin delivered during the last 20 min. Glucose was then decreased to 0 mM until the end of the experiment. (B) The measured extracellular glucose concentration is shown for HepG2 perfused with an initial 0 mM glucose followed by 200 nM insulin in 10 mM glucose. Insulin was then removed, and 10 mM glucose was delivered without insulin for 15 min followed by perfusion with 0 mM glucose to the end of the experiment.