Recently we experienced one patient of the islet cell tumor who was frequently attacked with a typical hypoglycemia. We measured the blood glucose level and found it was severely hypoglycemic. The fasting test was positive and a long duration of severe hypoglycemia was observed on the tolbutamide test. We also determined the serum insulin-like activity in this patient by the method with the hypophysectomized-adrenolectomized rats, that was 8.6 mu/ml and twice higher than that of normal. After tolbutamide was injected intravenously, the insulin-like activity elevated to 21.0 mu/ml. This prominent elevation may be considered to be specific for insuloma. From these data we diagnosed his disease as insuloma. On laparotomy we resected a tumor in size of the first finger from the head part of his pancreas. On the histological examination, it was found to be a benign islet cell adenoma in which the content of zinc and β-granules decreased. The amount of insulin in this tumor was 4.89u/g and it was twice higher than that of normal. The decrease of β-granules in the tumor does not coincide with the amount of insulin, but this may be due to the specificity of this kind of tumor. After the operation, the patient has never suffered from the seizure of hypoglycemia.
A study was made on correlations between carbohydrate metabolism and factors related to it, i.e., aging, obesity and disturbances of the liver. Also diagnostic criteria for diabetes mellitus were discussed. The subjects consisted of 360 apparently healthy people who had received complete medical examinations including glucose tolerance test (GTT) at the Center for Adult Diseases, Osaka. Cases of overt diabetes diagnosed on GTT were excluded. As a result, a mild impairment of carbohydrate metabolism which showed two-hour level of 120mg/dl or over on GTT, was found in 118 cases out of the 360 subjects. It was also found that aging, obesity and disturbances of the liver played an important role in the elevation of a twohour blood glucose level. These factors seemed to influence carbohydrate metabolism individually. For example, in cases without obesity of disturbances of the liver, the blood glucose level for one hour, as well as two hours, showed a trend of elevation as age advanced. On the basis of the pattern of GTT curves, cases with mildly impaired carbohydrate metabolism were classified into the following four types. Over half the cases were belonged to a type showing high values at one- and two-hour blood glucose levels (designated as P type). The rest belonged to D type which showed slightly high values at two- and three-hour levels, and atypical type which showed abnormal values only at two-hour level. Besides the above-mentioned cases, there was F type which showed high fasting values with normal other values. The cases belonging to these four types were followed up for one to two years. As a result, it was found that few cases belonging to P type and atypical type developed diabetes. On the other hand, considerably many cases of D type developed diabetes. It was supposed to conclude that the mild impairment of carbohydrate metabolism found in the present subjects was mostly based on aging, obesity and disturbances of the liver. It was stressed that the following points should be taken into consideration in interpreting GTT:(1) Aging should be considered as a factor which influences carbohydrate metabolism. (2) No generalized standards should be applied to cases with obesity or disturbances of the liver. A diagnosis of such cases must be established after a complete follow-up with assurance of their prognosis.
The clinical findings of 183 patients with diabetes mellitus, 125 males and 58 females, during these 10 years at our clinic were analyzed statistically. These patients have had the disease from 0 to 42 years and the average duration is42 years. The age distribution was from 15 to 72 years old and approximate 70% of patients studied were those between the ages of fifty and sixty-nine. The following results were obtained. 1) Proteinuria and hypertension were present in 32.0% and 36.6% of all patients studied, respectively. Forty (28.2%) of 142 patients whose eye grounds were examined had diabetic retinopathy. 2) These complications were more apt to occur in females and increased in incidence in those patients with diabetes mellitus of over 6 years'duration. 3) Co-existence of triad of proteinuria, hypertension and diabetic retinopathy was found in twenty-three (16.2%) of 142 patients and its incidence was correlated with the duration of the disease. In this group, massive proteinuria, edema, hypercholesterolemia and hypoalbuminemia were frequently noted. The nephrotic syndrome developed in 4 cases of these 23 patients. 4) The correlation between renal functional disturbances and proteinuria was noted most remarkably amoung various clinical findings. Especially, the renal function of patients with proteinuria, hypertension and retinopathy was more markedly disturbed than that of other groups. It is also suggested that the functional disturbances of diabetic kidney were not a simple function of the duration of the disease.