PARTIALLY DEACETYLATED CHITIN AND HYALURONAN INDUCE GLYCOGENOLYSIS INPERFUSED-RAT-LIVER

Mannan interacts with mannose/N-acetylglucosamine (GIcNAc) receptors o n the surface of both Kupffer cells and endothelial cells in the liver , and induces glycogenolysis through production of peptide-leukotriene (LT) in the perfused rat liver, In the present study, we examined whe ther positively and negatively charged GlcNAc-containing polysaccharid es stimulate glycogenolysis in perfused rat liver, Infusion of the for mer, 67% deacetylated chitin (DAC), induced biphasic increases in gluc ose production and a steep decrease in oxygen consumption by the liver , ONO-1078, an LT D-4 receptor antagonist, abolished the suppression o f oxygen consumption and reduced the glucose production by DAC, Infusi on of the latter, hyaluronan, stimulated glucose production with a con comitant increase in oxygen consumption, Ibuprofen, a cyclooxygenase i nhibitor, reduced the glucose production by hyaluronan, Sequential inf usions of mannan and DAC, but not hyaluronan, did not induce glycogeno lytic responses when mannan was infused 20 min before the second stimu lation, These results suggest that DAC, but not hyaluronan, stimulates mannose/GlcNAc receptors in the perfused rat liver, and that potent i mmunological activity induced by DAC may be mediated by activation of the receptors.