Plasma myoinositol in diabetics including patients with renal allografts

Summary

Since decreased tissue myoinositol (inositol) content in experimental diabetes has been reported, plasma inositol in diabetics after 3 g oral loads of inositol was studied. Diabetics with normal renal function had inositol intolerance with plasma inositol values significantly higher than controls at 3, 4 and 5 h (p<0.05). The fasting values were not different from those seen in normals. Strict control of hyperglycemia with insulin resulted in a significant improvement in inositol tolerance at 3 h (p<0.02), 4 and 6 h (p<0.05), although the values were still higher than in normals (p<0.05 at 5 h). Diabetics with renal allografts for 2 to 4 years had normal inositol tolerance, as long as their renal function remained normal. Diabetics with creatinine clearance of 65 ± 6 ml/min, with and without renal allografts, had significantly increased fasting and post-inositol load plasma concentrations. Oral inositol did not change plasma insulin concentration. In conclusion, there seems to be an abnormality of inositol metabolism in diabetes, independent of clinically detectable renal disease, and at least partially correctable by insulin treatment. Since only recent kidney allograft recipients had normal inositol tolerance, the defect may result from abnormal renal inositol catabolism in kidneys exposed to hyperglycemia for several years.