Determination of Ca2+-atpase activity in streptozotocin-induced diabetic rat liver.
Microsomal Ca2+-ATPase activity was studied in control and streptozotocin (STZ)-induced diabetic rat livers. Male rats were rendered diabetic by injection of STZ (45 mg/kg body weight) via the tail vein. Diabetic rats at 1, 4, 8, 10 or 15 wk and control rats were sacrificed. Liver tissues were obtained for the isolation of Ca2+-ATPase. Ca2+-ATPase activity was determined spectrophotometrically and lipid peroxidation [measured as tiobarbituric acid reactive substances (TBARS)] in liver tissues was determined spectrofluorometrically. Total calcium was measured by atomic absorption spectrophotometry. Blood glucose levels of the diabetic animals were >500 mg/dl at 4, 8, 10 and 15 wk of diabetes. Ca2+-ATPase activity was significantly decreased at all weeks of diabetes compared to control group (p<0.001). Ca2+-ATPase activity of control rats was 0.193 +/- 0.015 U/I whereas activity was 0.130 +/- 0.015 U/I at 15 wk of diabetes. The difference in calcium levels of diabetic rat livers was not significantly different compared to control group. On the other hand TBARS were elevated by 67% at 15 wk of diabetes. The decrease in enzyme activity may have been caused by elevated TBARS levels observed in liver tissue sindicative of increased lipid peroxidation.
Pekiner
B Dogru
BD
Department of Biochemistry, Faculty of Pharmacy, University of Ankara, Tandoğan, Turkey.
Daş
Evcimen N
EN
Nebioğlu
S
S
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000378:metabolism; D015227:Lipid Peroxidation; D008099:Liver / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D013053:Spectrophotometry; D013311:Streptozocin; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D001786:Blood Glucose; D017392:Thiobarbituric Acid Reactive Substances; D013311:Streptozocin; D000252:Calcium-Transporting ATPases; D002118:Calcium