Active not recruitingNAINTERVENTIONAL

Relative Contribution of Brain Insulin Action for Postprandial Metabolism

This research wants to understand how the insulin that reaches your brain helps control how your body uses sugar after you eat. We're also checking if this process is different in men compared to women, and if a woman's monthly cycle has any effect. Participants will be given a sugar drink (like a standard test for diabetes) and either an insulin spray that goes to the brain or a placebo (dummy) spray. By comparing these, researchers hope to see if brain insulin control changes how your body handles sugar, produces its own sugar, and makes important hormones. This could lead to a better understanding of sugar-related conditions in the future.

At a glance

Status

Active not recruiting

Phase

Sponsor

University of Ulm

Enrolment target

Start

18 Mar 2024

Estimated completion

01 Jun 2026

Glucose Metabolism Disorders

What is this study about?

Imagine your body as a carefully balanced system, especially when it comes to how you use sugar for energy after you've eaten. We know that insulin, a hormone made in your body, plays a key role in this. But what about the insulin that specifically acts in your brain? This study is designed to answer a really interesting question: How much does the insulin working in your brain actually contribute to how your whole body handles sugar after a meal?

To find this out, we'll be asking volunteers to take part in two special test days. On one day, they will receive a tiny amount of insulin through a nasal spray, which helps it reach the brain. On another day, they'll get a 'dummy' spray (called a placebo) that doesn't contain insulin. Both times, they'll also have a sweet drink, similar to what's used in a standard diabetes screening test. By carefully comparing what happens in the body on these two days, the researchers can see what difference brain insulin makes.

This research is particularly interested in understanding if there are any differences between men and women in how the brain controls sugar use. For women taking part, the study will also look at whether their monthly cycle influences how brain insulin works to manage sugar. By learning more about these connections, we can gain a clearer picture of how our bodies keep sugar levels balanced, which could be important for understanding and eventually helping people with sugar-related health conditions.

Key takeaways

This study explores how your brain's insulin affects sugar use after meals.
It aims to identify differences between men and women.
The research also considers the impact of a woman's menstrual cycle.
You'll receive a nasal spray (insulin or dummy) and a sugary drink.
Participation involves a few visits and blood tests over several hours.
The findings could improve our understanding of sugar-related health issues.

Who may be eligible?

This study is looking for healthy volunteers. To take part, you need to be a young adult, specifically between 18 and 30 years old. Your Body Mass Index (BMI) should be under 24, which is generally considered a healthy weight.

It's important that you don't have any major ongoing health conditions, and for women, you shouldn't be using any hormone-based contraception. We also need to check your blood at the beginning to make sure your iron levels are healthy – specifically, for women, your haemoglobin should be at least 12 g/dl, and for men, at least 14 g/dl.

There are also some things that would mean you can't join the study. These include if you smoke, or if you misuse alcohol or drugs. If a doctor feels that taking part in the study could put your safety at risk or affect the quality of the research, you wouldn't be able to participate.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 30 years old?
Is your BMI (Body Mass Index) less than 24?
Do you have any major ongoing health conditions?
Are you a woman who is not using hormonal birth control?
Do you smoke or misuse alcohol/drugs?
Are you generally healthy and feel well?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll visit the research centre for a few appointments. You will have two main study days. On these days, you'll be given a nasal spray (either with insulin or a dummy spray) about 15 minutes before you drink a special sugary liquid. This liquid contains tiny, harmless 'tracers' that help us track how your body uses sugar. Blood samples will be taken regularly (through a temporary cannula, a small tube in your arm) over several hours after you drink the sugar solution to measure various things like your sugar levels and hormone responses. On the day you receive the dummy spray, you might also be given a very small, controlled amount of insulin through an IV into your arm. Each of these study days will last for several hours. The total duration of your participation in the study, from your first screening visit to your last study day, will be communicated to you by the study team.

Potential risks and benefits

Taking part in this study won't directly benefit your health, but the information we gather will be very valuable in helping us better understand how the brain controls sugar use, which could lead to improvements in understanding conditions like diabetes in the future. As with any medical study, there are some minor risks, such as discomfort from blood draws. The nasal spray may cause some temporary irritation. You will be closely monitored by medical staff throughout the study. Remember, your participation is voluntary, and you have the right to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Universityhospital Ulm
Verified postcode
Ulm, Germany

Common questions

What is an oral glucose tolerance test?

It's a common test where you drink a sugary liquid, and then your blood sugar levels are checked over a few hours to see how your body handles sugar.

Will the nasal spray hurt?

The nasal spray is generally well-tolerated, but you might feel a slight sting or irritation in your nose for a very short time.

What are 'tracers' and are they safe?

These are special, harmless sugars that are naturally present in tiny amounts and allow researchers to follow how your body processes sugar. They are completely safe and cleared from your body naturally.

Will I know if I get the insulin or the dummy spray?

No, this is a 'blinded' study, meaning neither you nor the research staff will know which spray you receive on which day. This helps keep the results unbiased.

How long will each study day take?

Each of the main study days will involve several hours at the research centre while measurements are taken after you've had the sugar drink.