title: Immunoreactive gastric inhibitory polypeptide response to a meal during the first eighteen months after diagnosis of type 1 (insulin dependent) diabetes mellitus.
abstract: The changes in plasma concentrations of immunoreactive gastric inhibitory polypeptide (IR-GIP) in response to a standard meal were examined in 21 normal subjects and 15 Type 1 (insulin dependent) diabetic patients 7 days, 14 days, and 3, 6, 9, 12, and 18 months after time of diagnosis. During the first 4 tests significantly lower plasma IR-GIP concentrations were found in the diabetic patients after the standard meal. At 9 months and during the remaining tests there was no difference in IR-GIP concentrations between the diabetic and the normal subjects. The IR-GIP response was normalized faster if the diabetic patients were treated with initial short term intensive insulin therapy than if they were treated conventionally with 1 or 2 daily injections of insulin. beta-Cell function, evaluated by the C-peptide response to the meal, increased significantly during the first 3 months. After 3 months maximal beta-cell function was found while the corresponding IR-GIP responses were significantly lower than those of the normal subjects. Thereafter beta-cell function declined gradually and significantly, coinciding with the normalization of the IR-GIP response. No individual covariation between IR-GIP and beta-cell function during the 18 months was found in any patient. The IR-GIP response to a meal was diminished at the onset of Type 1 (insulin dependent) diabetes mellitus. After the start of insulin therapy the response improved, perhaps as a function of the quality of metabolic control, and within a year it was comparable to that of normal subjects. Lack of endogenous GIP therefore does not explain the diminished beta-cell function in Type 1 diabetes a few months after onset of the disease. No causal relationship between the changes in beta-cell function and IR-GIP during the first 18 months after the onset of the disease seems to exist.
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D004435:Eating; D005215:Fasting; D005260:Female; D005749:Gastric Inhibitory Polypeptide / Q000097:blood / Q000378:metabolism*; D005768:Gastrointestinal Hormones / Q000378:metabolism*; D006801:Humans; D007118:Immunoassay; D007328:Insulin / Q000378:metabolism / Q000627:therapeutic use; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000503:physiopathology; D008297:Male; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D005768:Gastrointestinal Hormones; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide