Effect of Glucagon on Fasting Insulin Secretion and Glucose Metabolism in Subjects Without Type 2 Diabetes

Mayo Clinic

Status: Enrolling

Conditions: PreDiabetes

Treatments: Other: Glucose; Other: Glucagon

Study type: Interventional

Funder types: Other

Identifiers

NCT06424106

24-002639

Details and patient eligibility

About

Fasting hyperglycemia contributes disproportionately to nonenzymatic glycosylation and the microvascular complications of type 2 diabetes. However, little is known about the regulation of glucose concentrations in the fasting state relative to what is known about the postprandial state. The proposed experiment is part of a series of experiments designed to establish how glucagon and insulin interact with their receptors to control fasting glucose in health and in prediabetes.

Full description

The interaction between α-cell and β-cell function to regulate fasting glucose is incompletely understood. This is an important gap in our knowledge as fasting glucose contributes disproportionately to HbA1c and the microvascular complications of type 2 diabetes (T2DM). The regulation of fasting glucose in health and disease is relatively understudied.

Insulin and glucagon should regulate glucose reciprocally through direct interaction; insulin restrains α-cell secretion while glucagon directly stimulates β-cell secretion. In addition, there are indirect interactions via changes in glucose. Glucagon increases endogenous glucose production (EGP) increasing glucose (and insulin secretion). Conversely, insulin stimulates glucose disappearance (Rd) and suppresses EGP, lowering glucose (and stimulating glucagon).

However, this does not appear to occur uniformly in prediabetes. For example, in impaired fasting glucose (IFG), glucagon secretion rate (GSR) is inappropriate for the prevailing glucose. This is not accompanied by reciprocal changes in insulin secretion rate (ISR). Variability in the hepatic response to glucagon and to insulin further compound the dysregulation of fasting glucose. The net effect of these variables is unknown. This experiment is intended to test the hypothesis that impaired glucagon-induced insulin secretion contributes to fasting hyperglycemia in IFG.

Enrollment: 60 estimated patients

Sex: All

Ages: 25 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Individuals with normal or impaired fasting glucose and normal or impaired glucose tolerance

Exclusion criteria

• HbA1c less than 6.5%
• Use of any glucose-lowering agents including metformin or sulfonylureas.
• For female subjects: positive pregnancy test at the time of enrollment or study
• History of prior upper abdominal surgery such as adjustable gastric banding, pyloroplasty and vagotomy.
• Active systemic illness or malignancy.
• Symptomatic macrovascular or microvascular disease.

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Sequential Assignment

Masking: None (Open label)

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60 participants in 2 patient groups, including a placebo group

Glucagon Infusion

Active Comparator group

Description:

A glucagon infusion (0.2 ng/kg/min) will start at 0900 (0 min), increasing to 0.4 (1000), 0.6 (1100) and 0.8 ng/kg/min (1200) at 60-minute intervals - ending at 1300 (240 min).

Treatment:

Other: Glucagon

Glucose Infusion

Placebo Comparator group

Description:

At 0900 (0 min) a glucose infusion will commence, and the infusion rate varied to replicate (± 5mg/dL) that individual's glucose concentrations observed during the Glucagon Infusion Day. The experiment will end at 1300 (240 min) when infusions are stopped.

Treatment:

Other: Glucose