Objective: To evaluate the beta cell functions with and without human Isophane insulin treatments.
Methods: Thirty patients with type 2 diabetes mellitus who followed the human Isophane insulin therapeutic regimen at bedtime were given 100 g steamed bread tests in two consecutive days. Then the human Isophane insulin treatments were stopped and the 100 g steamed bread tests were repeated in the next day. The fasting and 1, 2, 3 h after meal plasma glucose, serum insulin, C-peptide and proinsulin were measured.
Results: (1) The fasting and 1,2,3 h after meal plasma glucose increased while the serum insulin decreased after the human Isophane insulin treatments were stopped (P<0.05). (2) The fasting and 1, 2 h after meal C peptide increased (P<0.05) after the human Isophane insulin treatments were stopped. (3) The fasting and 1, 2, 3 h after meal proinsulin increased after the human isophane insulin treatments were stopped (P<0.05). (4) The area under the insulin curve decreased, while, the area under the C peptide increased after the human Isophane insulin treatments were stopped (P<0.05).
Conclusion: Human Isophane insulin treatments should not be stopped to evaluate the beta cell functions of the patients who are undergoing Isophane insulin treatment.