Submitted on March 10, 2005
Accepted on June 17, 2005
Route dependent effect of nutritional support on liver glucose uptake
Sheng-Song Chen1, Carlos J Torres-Sanchez1, Nadeen Hosein1, Yiqun Zhang1, D. Brooks Lacy1, Chris Chang1, and Owen P McGuinness1*
1 Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
* To whom correspondence should be addressed. E-mail: owen.mcguinness{at}vanderbilt.edu.
The liver is a major site of glucose disposal during chronic (5 days) total parenteral (TPN) and enteral (TEN) nutrition. Net hepatic glucose uptake (NHGU) is dependent upon the route of delivery when only glucose is delivered acutely, however the hepatic response to chronic TPN and TEN is very similar. The aims were to determine if the route of nutrient delivery altered the acute (first 8 h) response of the liver and if chronic enteral delivery of glucose alone could augment the adaptive response to TPN. Chronically catheterized conscious dogs received either TPN or TEN containing glucose, Intralipid and Travasol either for 8 h or 5 days. Another group received TPN for 5 days but ~50% of the glucose in the nutrition was given via the enteral route (TPN+EG). Hepatic metabolism was assessed using tracer and arterio-venous difference techniques. In the presence of similar arterial plasma glucose levels (~6 mM) NHGU and net hepatic lactate release increased ~2-fold between 8h and 5 days in TPN and TEN. NHGU (26±1 vs.23±3 µmol/kg/min) and net hepatic lactate release (44±1 vs. 34±6 µmol/kg/min) in TPN+EG were similar to TPN, despite lower insulin levels (96±6 vs. 58±16 pM; TPN vs. TPN+EG). TEN does not acutely enhance NHGU or disposition above that seen with TPN. However partial delivery of enteral glucose is effective in decreasing the insulin requirement during chronic TPN.
