Influence of Insulin Status on Extra-Mitochondrial Oxygen Metabolism in the Rat

Abstract

The effects of alloxan diabetes and subsequent treatment with insulin on extra-mitochondrial oxygen metabolism in terms of D-amino acid oxidase (DAAO), xanthine oxidase and catalase were examined. The DAAO activity in the liver with D-alanine and D-serine decreased by 33-62% in the diabetic group while the decrease in the kidneys was 61-74%. Insulin treatment resulted in overstimulation of DAAO activity in the liver but not in the kidneys. Tissue glycogen content was lowered in the diabetic animals but was restored by insulin treatment. Tissue glycogen content and DAAO activity showed an inverse relationship. The xanthine oxidase activity in the two tissues decreased from 40-55%; the catalase activity decreased from 34-54%. Insulin treatment was unable to restore the xanthine oxidase and catalase activities in both the tissues.

Pleurotus ostreatus, an edible mushroom, enhances glucose 6-phosphate dehydrogenase, ascorbate peroxidase and reduces xanthine dehydrogenase in major organs of aged rats

“…Oxidative stress and O À 2 , ROS, can also originate from extra-mitochondrial systems such as microsomal electron transport chain and other enzymes such as xanthine oxidase, aldehyde oxidase, dihydroorotic dehydrogenase and a group of flavoprotein dehydrogenases (Satav et al, 2000). The ascorbate-glutathione cycle, also known as the Halliwell-Asada or water-water cycle, utilizes serial enzymes, Apx, dehydroascorbate reductase, GR and monodehydroascorbate reductase to scavenge superoxide radicals and H 2 O 2 in chloroplasts (Asada, 1999).…”

Diabetic cardiomyopathy and reactive oxygen species (ROS) related parameters in male and female rats: A comparative study

“…The increase in XO activity is a matter of concern since XO is recognized as one of the extra-mitochondrial sites of superoxide (O 2¯) generation (26,34). O 2¯ generated extramitochondrially should be eliminated in the first instance by SOD of the post-mitochondrial fraction.…”

“…At the starting of the experiments, the initial body weights in the male groups ranged from 230-250 g while these values for the female groups were in the range of 210-220 g. The initial body weights of male and female rats belonging to various experimental groups (details given below) were matched within 5 g. The animals were fasted overnight and diabetic state was induced by injecting once 12 mg of alloxan/100 g body weight subcutaneously (s. c.) (33)(34)(35). Alloxan solution was prepared fresh in saline (120 mg/ml) prior to use.…”

“…Xanthine oxidase activity (XO), (P mole DCIP reduced/min/mg protein) was estimated by the methods discribed (34,41). Superoxide dismutase (SOD) activity (units/mg protein; 1 unit represents the amount of enzyme required for 50 % inhibition of pyrogallol autoxidation under standard assay conditions) was determined by the procedures described previously (42,43).…”

“…Superoxide dismutase (SOD) activity (units/mg protein; 1 unit represents the amount of enzyme required for 50 % inhibition of pyrogallol autoxidation under standard assay conditions) was determined by the procedures described previously (42,43). Estimation of catalase activity (Sigma units/mg protein), was according to the method of Satav et al (34). Measurement of glutathione peroxidase (GPox) activity (units/min/mg protein) was carried out by the procedure of Hafeman et al (44).…”