We have re-examined Sluiter et al's report in which they proposed a mathematical approximation of two independent parameters, the beta-cell response and the peripheral insulin activity after 100g OGTT. It was confirmed that there exists a straight-line relationship between G and I/G for each individual during the early period after the glucose loading. Furthermore, we were able to deduce a very similar equation to theirs for the corrected insulin response as CIR = I₃₀-100/G₃₀ (G₃₀-70) from the mean slope of the straight-line obtained from data of non-obese healthy subjects. There exists a definite correlation between CIR and insulinogenic index. Also, peripheral insuln activity (A) correlated well with insulin sensitivity indicies which were calculated from the speed of the blood glucose fall following a single intravenous injection of insulin.
By these means, we have observed the following:
1) The more obese person had a higher CIR and a smaller A.
2) There were no specific differences in either of the parameters according to age and sex.
3) CIR and A showed a concomitant decrease, as glucose tolerance diminished. In patients with diabetes mellitus, however, only CIR decreased further when FBS exceeded 120 mg/100 ml.
4) Patients with chronic liver diseases revealed a significantly higher CIR and smaller A, when compared with control subjects who showed the same degree of glucose tolerance.
5) 10 hrs after an oral administration of 2 mg dexamethasone, a significant decrease in A was observed, while 8 of 10 persons showed increases in CIR.