Since the development of the insulin radio-immunoassay, there have been many reports on the response of this hormone to glucose stimulation. Descriptions vary widely and considerable controversy still exists as to whether hypo- or hyper-insulinaemia following an oral glucose load is the characteristic response in patients with maturity-onset diabetes. The relationship of plasma insulin levels to an oral glucose load in subjects with a wide spectrum of glucose tolerance has been examined in an urbanized Micronesian population (Nauru). This population with a high incidence of obesity has been shown to have one of the highest diabetes prevalence rates yet recorded. Oral glucose tolerance tests were performed on 209 subjects and a 75 gm glucose load was used. The subjects were separated into six groups on the basis of two-hour plasma glucose levels, and the patterns of insulin response were examined. The two-hour plasma insulin levels were highest in the group with two-hour plasma glucose levels 7.8 - 11.0 mmol/l. (140 - 199 mg/100 ml). In the groups two-hour plasma glucose 5.6 - 7.7 mmol/l. (100 - 139 mg/100 ml) and 15.6 - 22.2 mmol/l. (280 - 399 mg/100 ml), plasma insulin levels were similar and significantly higher than that of the 0 - 5.5 mmol/l. (0 - 99 mg/100 ml) category. However, as glucose levels rose further to above 22.2 mmol/l. (400 mg/100 ml), insulin levels fell progressively and became significantly less than the 0 - 5.5 mmol/l. (0 - 99 mg/100 ml) group. These results confirm those reported in the Pima Indians. This study suggests that different interpretations of insulin responses in subjects with maturity-onset diabetes result from comparison of groups with different degrees of impaired glucose tolerance. There is clearly a wide range of insulin response to oral carbohydrate and this appears to be dependent on the post-load glucose level. Both hypo- and hyper-insulinaemia may occur in the natural history of maturity-onset diabetes.
|Number of pages||1|
|Journal||Proceedings of the Endocrine Society of Australia|
|Publication status||Published - 1977|