Erythrocyte arginase activity and serum nitric oxide in diabetes mellitus

The study is to estimate and correlate the erythrocyte arginase activity and serum nitric oxide levels in normal, prediabetes and type 2 diabetes mellitus. This is a case control study with total 124 samples which were grouped as normal, pre-diabetes and diabetes based on HbA1C values. Blood samples were collected from Clinical Biochemistry laboratory, Kasturba Hospital, Manipal, after the completion of HbA1C analysis. Erythrocyte Arginase activity is estimated by measuring the ornithine formed by Chinard reaction and Arginase activity is expressed as ornithine released per minute per gram hemoglobin under assay conditions. Nitric oxide is estimated by reducing the serum nitrate to nitrite by using Griess reaction method. The increase in arginase activity was seen in both prediabetes and diabetes compared to normals. Compared to normal group, there was significant decrease in nitric oxide level in pre diabetes (P=0.013) however decrease is not significant in type 2 diabetes. Significant positive correlation between the arginase and nitric oxide levels is seen in normals and type 2 diabetes whereas negative correlation in prediabetes. Increase in arginase activity is indirectly affecting the nitric oxide levels and causing the macrovascular (atherosclerosis, hypertension, gangrene of foot, diabetic neuropathy) and microvascular (diabetic nephropathy, diabetic retinopathy) complications in type 2 diabetic patients.