28 young diabetics with short disease duration participated in a double-blind study by taking 6 g of myoinositol or placebo daily for 2 months. The aim was to demonstrate a possible beneficial effect of this compound on subclinical diabetic neuropathy. Measurement of vibratory perception threshold, motor and sensory conduction velocity and amplitude of nerve potential did not disclose any effect of the myoinositol given. In accordance with this, no indication for a lack of myoinositol in human diabetic blood or tissue could be found. The concentration of myoinositol in the plasma and erythrocyte of 4 human diabetics was normal or high, even though the loss of urinary myoinositol was greater than in the case of 4 normals. Further, an analysis of the content of free and lipid-bound myoinositol in muscle biopsies taken from the 4 diabetics did not give any indication of deficiency. The content of myoinositol in their muscle tissue remained uninfluenced by oral supplementation of myoinositol.

The isotopic dilution technique was used for determining the content of myo-inositol in human urine, plasma and haemolysed erythrocyte samples. A deuterated myo-inositol, synthesized from inosose-2 by base-catalysed exchange of hydrogens by deuterium, followed by reduction of the inosose with 2H2, was added as internal standard to the samples at an early stage in the analytical procedure. After separation and derivatization to the hexa-acetate, the gas chromatographic mass spectrometric analysis was carried out. A 25 m fused silica capillary column coated with methyl silicone was used, and the ions selected for monitoring were m/z 210 and m/z 214, which are characteristic and abundant fragment ions from unlabelled and hexadeuterated myo-inositolhexa-acetate, respectively. Calibration curves from water, urine, plasma and haemolysed erythrocytes show parallel, linear responses in the ratio between analyte and internal standard in the area of interest (0.2-2.0).