An 'artificial beta cell' for control of diabetes mellitus: effect on plasma glucagon levels.

We have investigated the use of a glucose-controlled insulin infusion system, or artificial beta cell. On the feedback day, mean plasma glucose was significantly effect of improved control on plasma glucagon levels. Five insulin-requiring diabetic subjects in stable control were hospitalized for two 24 h periods. During one, they were given their usual dose(s) of subcutaneous insulin. In the other, the 'feedback' day, insulin administration was under feedback control by the artificial beta cell. One the feedback day, mean plasma glucose was significantly-lower in all subjects. Variability in plasma glucose throughout the day was also significantly less on the feedback day. All five subjects showed a significant fall in serum immunoreactive glucagon levels on the feedback day, suggesting that the glucagon abnormalities of diabetes may be secondary to the insulin deficiency, rather than a second primary defect of diabetes.