[Study of the "dawn phenomenon" using an artificial endocrine pancreas].

30 insulin-dependent, C-peptide negative diabetic patients were examined with the help of biostator. The mean age of the patients was 29 years, the mean duration of the diabetes was 7 years and the mean index of body mas was 22. For the period from 0 to 8 o'clock in the morning the blood sugar level and the speed of the insulin infusion in order to maintain euglycemic level were examined at 1/2 hour intervals. The mean blood sugar level for the period 5-8 o'clock (5.71 +/- 0.31 mmol/l) was reliably higher (p less than 0.05) than that for the period 0-5 o'clock (5.4 +/- 0.18 mmol/l). The speed of the insulin infusion for the period 5-8 o'clock (0.52 +/- 0.09 IU/kg/min) was also reliably higher (p less than 0.02) than that for the period 0-5 o'clock (0.4 +/- 0.06 IU/kg/min). These two indices were correlated with the somatotropic hormone and hydrocortisone levels at 2 and 8 o'clock. The possible pathogenetic mechanisms of this "morning phenomenon" in diabetes is discussed.