Glucagon Responses During Oral- and iv Glucose in Patients With Type 1 Diabetes

Study Overview
=================
Brief Summary
-----------------
In order to evaluate the potential role of the gastrointestinal (GI) tract in the postprandial hyperglucagonemia, which characterizes type 1 diabetes mellitus (T1DM) (as well as type 2 diabetes mellitus (T2DM)), we wish to investigate the secretion of glucagon in patients with T1DM without residual beta-cell function during 50-g oral glucose tolerance test (OGTT) and during isoglycemic iv glucose infusion. By evaluating C-peptide negative patients with T1DM we aim to describe the glucagon response to glucose (+/-stimulation of the GI tract) independently of the potentially very important regulation of glucagon secretion by endogenous insulin secretion. A more detailed understanding of the inappropriate glucagon secretion in T1DM is highly needed in order to establish new intervention strategies in the future treatment of the growing numbers of T1DM patients.

Official Title
-----------------
Glucagon Responses Following Oral Glucose and Isoglycemic iv Glucose in Patients With Type 1 Diabetes - a Role for the Gastrointestinal Tract in Diabetic Hyperglucagonemia?

Conditions
-----------------
Hyperglucagonemia, Hyperglycemia, Diabetes Mellitus

Intervention / Treatment
-----------------
* Other: Oral glucose tolerance test
* Other: Isoglycemic iv glucose infusion


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Caucasian over 18 years with T1DM (diagnosed according to WHO's criteria) treated with long-acting insulin No residual beta-cell function (arginine test without increment in plasma C-peptide - see below) BMI <30 kg/m2 Normal haemoglobin Informed consent Exclusion Criteria: Residual beta-cell function (increment in plasma C-peptide during arginine test - see below) Known liver disease or affected liver enzymes (ALAT/ASAT > 2 x upper normal limit) Diabetic nephropathy (se-creatinin > 130 µM and/or albuminuria) Proliferative diabetic retinopathy (anamnestic) Treatment with medication that cannot be discontinued for 14 hours

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 1<br>Patients with type 1 diabetes mellitus | Other: Oral glucose tolerance test<br>* 50 g of waterfree glucose dissolved in 300 ml water is ingested over 5 minutes following a 10-h fast including liquids and medication (if any).<br>* Other names: 50 g-OGTT;Other: Isoglycemic iv glucose infusion<br>* The plasma glucose curve obtained during a 50 g-OGTT (performed on a separate day) is copied using an adjustable iv glucose infusion (20% w/v) performed following a 10-h fast including liquids and medication (if any). The iv catheter is inserted into a peripheral vein in the hand/forearm.<br>* Other names: Isoglycemic IVGTT;|
| 2<br>Healthy control subjects matched for body mass index (BMI), age and gender. | Other: Oral glucose tolerance test<br>* 50 g of waterfree glucose dissolved in 300 ml water is ingested over 5 minutes following a 10-h fast including liquids and medication (if any).<br>* Other names: 50 g-OGTT;Other: Isoglycemic iv glucose infusion<br>* The plasma glucose curve obtained during a 50 g-OGTT (performed on a separate day) is copied using an adjustable iv glucose infusion (20% w/v) performed following a 10-h fast including liquids and medication (if any). The iv catheter is inserted into a peripheral vein in the hand/forearm.<br>* Other names: Isoglycemic IVGTT;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glucagon responses (as assessed by area under curve (AUC)) during 50-g oral glucose tolerance test (OGTT) and isoglycemic iv glucose infusion, respectively. |  | months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Responses of glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2) and glucose-dependent insulinotropic polypeptide (GIP) as assessed by AUC during 50-g OGTT and isoglycemic iv glucose infusion, respectively. |  | months | 
| GI-mediated glucose tolerance as assessed by the amount of glucose ingested as compared to the amount of glucose needed to mimic the OGTT curve during the iv glucose infusion. |  | Months |