Prednisolone glucose tolerance test (PGTT) and intravenous tolbutamide test were carried out in oxyhyperglycemic patients who were proved to have no history of gastrectomy, endocrine disorders, or liver diseases. Simultaneously, the shift of the serum IRI response or glucose tolerance through prednisolone loading were also examined with special reference to the relationship between oxyhyperglycemia and diabetes mellitus. Eighty-five oxyhyperglycemic cases without gastrectomy were selected for this study.
1) Of 65 cases of oxyhyperglycemia 40 cases (61.5%) showed positive PGTT.
2) The average rate in the initial fall of blood glucose after tolbutamide infusion showed an intermediate value of normal persons and clinical diabetics, but the response was very similar to that found in the probable diabetics or chemical diabetics who showed normal fasting blood glucose level. In fact, of 17 subjects 5 cases showed the diabetic pattern in Unger-Madison's criteria.
3) Of 29 subjects of oxyhyperglycemia 3 cases were found to be nondiabetic, while, 10 cases were probable diabetic and other 2 cases were diabetic in GTT examined a year later.
4) Although many cases of oxyhyperglycemia without gastrectomy (20 out of 30 cases) showed high IRI response more than 100 μU/ml after glucose load, the initial rise of IRI at 30 minutes was less as compared to maximum, besides, the time required for reaching maximum and that required for restoring were tended to have delayed as compared to the cases with gastrectomy. Therefore, the average IRI response curve was very similar to that observed in the probable diabetics.
5) The effect of prednisolone on the serum IRI response was not observed during PGTT in the group, of 10 cases with negative PGTT, however, a marked diminution in the initial rise of serum IRI was observed with prednisolone and made the IRI curve similar to that found in the cases of chemical diabetes during GTT in the group of 14 cases with positive PGTT.
6) It was concluded from these results that the oxyhyperglycemia without gastrectomy was different in nature from that with gastrectomy because the former was considered to be a type of abnormalities appeared at the early stage of primary diabetics.