Forelimb skeletal muscle and skin glucose uptake during Escherichia coli endotoxin shock in the dog.

We previously demonstrated an increase in gracilis muscle glucose uptake during endotoxin shock in the dog. The present study was completed to investigate this phenomenon in forelimb skeletal muscle and skin. The isolated forelimb preparation was used. Mongrel dogs were anesthetized with nembutal and heparinized. Shock was induced by i.v. infusion of E. coli endotoxin. When isolated forelimb temperature was maintained at contralateral intact forelimb temperature (which was always the same as core temperature), forelimb skeletal muscle and skin glucose uptake increased by 30 minutes of shock, and remained above control for the 4 hour shock period. Total forelimb blood flow decreased and the limb became severely hypoxic (mean venous PO2 = 24 mmHg). However, when the isolated forelimb temperature was not artificially maintained at contralateral intact forelimb temperature (same as core temperature), the isolated forelimb temperature fell approximately 3 degrees C and the elevation of glucose uptake was not observed. Although forelimb blood flow decreased to the same level as in the temperature controlled group, the forelimbs were only moderately hypoxic. This study emphasizes the important influence of temperature on tissue metabolism and the recognition of its importance in experimental data interpretation, especially when metabolic variables are involved. It also demonstrates that changes in glucose uptake during shock are similar in dog forelimb skeletal muscle, provided that changes in muscle temperature are similar.