Oral glucose tolerance test with double-tracer dilution and atropine infusionOral glucose tolerance test with double-tracer dilution and saline infusion (placebo)
Oral glucose tolerance test with double-tracer dilution and atropine infusion: Subjects will undergo a 75 g oGTT (180 min) combined with a double tracer dilution. The double-tracer dilution technique will be used to quantify endogenous glucose production, glucose appearance and disappearance rate. \[6,6-2H\]glucose will be infused for a total of 300 minutes, while the infusion will start 120 minutes prior the oGTT and will last until the end of the oGTT. Atropine infusion will be administered 20 minutes before the start of the oGTT. The drink consumed at time point 0 min contains 75 gram glucose, enriched with \[U-13C6\]-glucose.
Oral glucose tolerance test with double-tracer dilution and saline infusion (placebo): Subjects will undergo a 75 g oGTT (180 min) combined with a double tracer dilution. The double-tracer dilution technique will be used to quantify endogenous glucose production, glucose appearance and disappearance rate. \[6,6-2H\]glucose will be infused for a total of 300 minutes, while the infusion will start 120 minutes prior the oGTT and will last until the end of the oGTT. Saline infusion will be administered 20 minutes before the start of the oGTT. The drink consumed at time point 0 min contains 75 gram glucose, enriched with \[U-13C6\]-glucose.
Study summary
The goal of this clinical trial is to evaluate the influence of parasympathetic transmission from the brain to different metabolic organs. This transmission can be blocked with the muscarinic antagonist atropine.
Participants will undergo an oral glucose tolerance test combined with a double tracer dilution technique either with atropine infusion or placebo.
Healthy individuals and high-risk individuals will be compared to identify possible changes in signaling in high-risk groups. In addition, men and women will be included to take into account possible sex differences.
Eligibility
Sex
ALL
Min age
18 Years
Max age
—
Healthy volunteers
Accepted
Inclusion Criteria:
* Age: at least 18
* BMI: 20 - 24.9 kg/m2 (for the healthy groups) or more than 28 kg/m2 (for the overweight groups)
* For women: Hormonal contraception with a single-phase preparation (e.g. Nuvaring)
* Understanding and voluntarily signing an informed consent form prior to study-related examinations
Exclusion Criteria:
* Drug and/or alcohol abuse
* smoking
* Taking medication that affects blood sugar or addresses the central and/or autonomic nervous system (e.g. anti-epileptic drugs, beta blockers, dopamine agonists, antidepressants). Taking antihistamines.
* Pre-existing cardiac conditions
* Neurological pre-existing conditions
* Known cardiac arrhythmia
* Known allergies to ingredients, e.g. paracetamol and atropine
* Known narrow-angle glaucoma
* Known hyperthyroidism
* Known diseases of the urinary tract or prostate
* Pregnancy or breastfeeding
* At screening: Hb \< 12 g/dl for women and Hb \< 14 g/dl for men
* No consent to be informed about incidentally discovered pathological findings
* Any (clinical) condition which, in the opinion of the physician, could jeopardize the safety of the
* or would jeopardize the scientific success.
* Liver dysfunction
* Renal insufficiency
Primary outcome measure(s)
Glucose tolerance — 120 minutes Effect of parasympathetic blockade with atropine versus placebo on glucose tolerance assessed as area under the glucose curve (0-120 minutes) and glucose levels at timepoint 120 minutes during the 75 g oral glucose tolerance test.
Insulin Sensitivity — 120 minutes Effect of parasympathetic blockade with atropine versus placebo on insulin sensitivity assessed from glucose and insulin measurements during the 75 g oral glucose tolerance test.
Insulin Secretion — 180 minutes Effect of parasympathetic blockade with atropine versus placebo on insulin secretion assessed from glucose and insulin/C-peptide measurements during the 75 g oral glucose tolerance test.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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