Graded Insulin Suppression Test P&F

What Was Tested

The trial (phase 1) is built around Glucagon and Octreotide for insulin resistance, prediabetes & type 2 diabetes.

The goal of this study is to learn about how the hormone insulin controls blood sugar in a variety of people.

The main question it aims to answer is about how much insulin the body actually needs to maintain a normal blood sugar level.

Participants will be asked to come in for a one-day study visit in which they will undergo a "graded insulin suppression test" ("GIST").

It had three arms (groups): Reference (healthy control) group (experimental), Euinsulinemic group (experimental) and Hyperinsulinemic group (experimental).

The registry classes the interventions as drug.

More on the Plan

The hypothesis is that some people with obesity and hyperinsulinemia exhibit a primary, non-compensatory hyperinsulinemia that may foment IR and its dysmetabolic sequelae.

If this were the case, lowering insulin levels should not result in a proportional rise in blood glucose as might be expected if the hyperinsulinemia truly were purely compensatory.

This hypothesis has been difficult to prove, however, because of the tight feedback mechanism between blood glucose and insulin secretion; under normal circumstances insulin secretion declines only alongside blood glucose.

As such, an attempt to lower insulin levels independently of blood glucose will raise blood glucose and trigger further insulin secretion, negating the purpose of the experiment.

Who Took Part

Enrollment: 20 actual participants took part.

It was open to people of any sex aged from 18 years up to 65 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: Body mass index of 18-25 and 30-45 kg/m2. Able to understand written and spoken English and/or Spanish. Fasting euinsulinemia (fasting serum insulin of 4-10 μU/mL) for reference group or hyperinsulinemia (fasting serum insulin ≥ 13 μU/mL) for hyperinsulinemic group on screening labs.

The full record lists 4 inclusion and 92 exclusion criteria; among the exclusions: unable to provide informed consent in english or spanish; unwillingness to use only bedpan or urinal to void or to refrain from non-emergent mobile device use during the gist; systolic blood pressure \< 90 mm hg or \> 160 mm hg, and/or.

How the Study Was Run

The set-up was non-randomized, parallel-group and open-label.

The Glucagon group and the comparison group ran side by side rather than switching.

Everyone knew when Glucagon was being given (open label), which is simpler to run but leaves more room for expectations to affect what is reported.

It started in 2024-09-16 with completion listed for 2026-10-13.

It ran at 1 site in United States.

Its stated primary purpose is basic science.

What Was Measured

The main thing measured (primary outcome): Steady-state plasma glucose at euinsulinemia (ESS-G) (time frame: 150-180 minutes during GIST protocol). Steady-state plasma glucose at hyperinsulinemia (HSS-G) (time frame: 270-300 minutes during GIST protocol).

It also tracked 3 secondary outcomes, for example Product of steady-state glucose and insulin at euinsulinemia (ESS-G x I), Product of steady-state glucose and insulin at hyperinsulinemia (HSS-G x I) and GIST index.

What This Means in Plain Language

Put simply, this is a phase 1, non-randomized trial of Glucagon and Octreotide in 20 people with insulin resistance, prediabetes & type 2 diabetes.

Its size is small, so on its own it can only give an early look.

The trial is marked completed; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Glucagon compound page and the Octreotide compound page, Insulin resistance, prediabetes & type 2 diabetes research.