Diabetes-induced decrease in rat brain microsomal Ca2+-ATPase activity.
The Ca(2+)-ATPase activity of rat brain microsomes was studied in streptozotocin (STZ)-induced diabetes. Male rats, 200-250 g, were rendered diabetic by injection of STZ (45 mg kg(-1) body weight) via the teil vein. Brain tissues were collected at 1, 4 and 10 weeks after diabetes was induced for determination of Ca(2+)-ATPase activity, lipid peroxidation and tissue calcium levels. Diabetic rats had significantly elevated blood glucose levels compared to controls. Blood glucose levels were 92.92 +/- 1.22 mg dl(-1) (mean +/- SEM) for the control group, 362.50 +/- 9.61 mg dl(-1) at 1 week and >500 mg dl(-1) at 4, 8 and 10 weeks for the diabetics. Enzyme activities were significantly decreased at 1, 4, 8 and 10 weeks of diabetes relative to the control group (p < 0.001). Ca(2+)-ATPase activity was 0.084 +/- 0.008 U l(-1), 0.029 +/- 0.005 U l(-1), 0.029 +/- 0.006 U l(-1), 0.033 +/- 0.003 U l(-1) and 0.058 +/- 0.006 U l(-1) (mean +/- SEM) at control, 1, 4, 8 and 10 week of diabetes respectively. The change in calcium levels in diabetic rat brain at 8 and 10 weeks of diabetes was significantly higher than that of the control group (p < 0.05). On the other hand lipid peroxidation measured as TBARS (thiobarbituric acid reactive substances) was significantly higher at 8 and 10 weeks of diabetes (p < 0.05). The increase in lipid peroxidation observed in diabetic rat brain may be partly responsible for the decrease in calcium ATPase activity.
Doğru Pekiner
Bilgehan
B
Department of Biochemistry, Faculty of Pharmacy, University of Ankara, Tandoğan, Turkey.
Daş Evcimen
Net
N
Nebioğlu
Serpil
S
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000378:metabolism; D015227:Lipid Peroxidation; D008297:Male; D008861:Microsomes / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin / Q000633:toxicity; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D001786:Blood Glucose; D017392:Thiobarbituric Acid Reactive Substances; D013311:Streptozocin; D000252:Calcium-Transporting ATPases; D002118:Calcium