Maximum activities of some key enzymes of glucose metabolism in livers of schistosoma mansoni infected mice

ABSTRACT

The effects of infection with Schistosoma mansoni [Saudi strain] on the maximal activities of glucose utilization pathways were studied in livers of mice during 16 weeks post-infection. The maximal activities of 6-phosphofructokinase and pyruvate kinase were significantly increased from week 4 indicating the increased capacity of the liver to utilize glucose, whereas the activity of glycogen phosphorylase was decreased as early as week 2, suggesting diminished hepatic glycogen break-down. Glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were significantly decreased from week 2 and 4, respectively. This suggested decreased flux through the pentose phosphate pathway in livers of infected animals. A significant decrease in the activities of citrate synthase and oxoglutarate dehydrogenase was observed at week 10 and 6, respectively, indicating diminished maximal capacity of the Kreb's cycle. All enzymatic changes [except Kreb's cycle enzymes] were detected prior to egg deposition [2-4 weeks] and are related, therefore, to the toxic products of growing worms. Such changes became more evident following egg deposition. Hepatic necrosis was observed at week 4 prior to egg deposition, which provides further evidence that factors released by worms can adversely affect the hepatic parenchyma. Necrosis, however, became more marked with the onset of egg deposition. The significance of these enzymatic changes, pathological findings and the underlying mechanisms are discussed