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.
Department of Biochemistry, Faculty of Pharmacy, University of Ankara, Tandoğan, Turkey.
Bilgehan
B
Doğru Pekiner
Net
N
Daş Evcimen
Serpil
S
Nebioğlu
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