Hemodynamic response to endotoxic shock is different in the newborn from the adult. As glucose transporters are developmentally regulated, glucose transporter responses to endotoxic shock may cause different glucose uptake in the heart between the newborn and the adult. The altered glucose uptake could help explain different hemodynamic responses. Ontogeny of glucose transporters, glucose transporter gene expression and glucose uptake during endotoxic shock were studied. Materials and Methods Zero day old, 10 day old and adult Sprague-Dawley rats were used after an ip injection of Salmonella enteritidis lipopolysaccharide (LPS) at LD90 dose. Rats without any injection were controls. Ontogeny of glucose transporters(GLUT1 and GLUT4) were examined with immunohistochemistry. Messenger RNA of GLUT1 and GLUT4 was measured 3 hours after LPS injection using Northern blot analysis. Glucose uptake was measured 3 hours after LPS injection in 10 day old and adult rats using [14C]-deoxy-glucose. Mean±SEM was calculated. ANOVA followed by Newman-Keuls test was used for statistical comparison of glucose uptake. Student-t test was used for statistical comparison of mRNA abundance.

Results GLUT1, a non-insulin-sensitive glucose transporter, was decreased and GLUT4, an insulin-sensitive glucose transporter, was increased with age. GLUT1 gene expression was increased (p<0.05) and GLUT4 gene expression was decreased (p<0.05) in all age groups 3 hours after LPS injection. Glucose uptake was increased 3 hours after LPS injection in 10 day old rats more (p<0.05) than in the adult rats.

Conclusion Non-insulin-mediated glucose uptake increases in the heart during endotoxic shock in the newborn more than the adult, probably due to the predominance of GLUT1 in the newborn. The altered glucose uptake may be responsible for different hemodynamic responses to endotoxic shock between the newborn and the adult.