When a fruit fly starts walking or flying, its insulin-producing cells are immediately inhibited. This could be one explanation for her why exercise improves health.
Insulin is an essential hormone for humans and many other organisms. Its best-known task is to regulate glucose metabolism. How to do this job is well understood. Little is known about how the activity of insulin-producing cells and the resulting insulin secretion is regulated.
A team from the Biocenter at the Julius Maximilian University (JMU) Würzburg in Bavaria, Germany, published news on this issue in a scientific journal. biology todayDr. Jan Ache’s group used Drosophila Drosophila melanogaster as their research object. Interestingly, this fly also secretes insulin after eating. However, in flies, hormones do not come from the pancreas as they do in humans, but instead are released from nerve cells in the brain.
Electrophysiological measurements in active flies
The JMU group found that physical activity in flies has a strong effect on insulin-producing cells. Drosophila.
Result: when Drosophila When the fly begins to walk or fly, its insulin-producing cells are quickly inhibited y. When the fly stops moving, the cell’s activity increases rapidly again, exceeding normal levels.
We hypothesize that the low activity of insulin-producing cells during walking and flight contributes to the supply of sugars to meet the increased energy demand. Increased post-exercise activity appears to help replenish energy stores such as the fly’s muscles.”
Dr. Sander Liessem, first author of the publication
blood sugar does not participate in regulation
The JMU team was also able to demonstrate that rapid, behavior-dependent inhibition of insulin-producing cells is actively controlled by neural pathways. is largely irrelevant,” explains co-author Dr. Martina Held.
It makes a lot of sense for the organism to anticipate increased energy demand in this way to prevent extreme fluctuations in blood sugar levels.
Insulin has changed little during evolution
Can you draw any conclusions about humans from the results? Probably.
“Insulin release in Drosophila is mediated by different cells than in humans, but the insulin molecule and its function have changed little during evolution,” says Jan Ache. In the past two decades using Drosophila as a model organism, many fundamental questions have already been solved that may also help us better understand human metabolic disorders and related diseases such as diabetes and obesity. there is.
Less insulin means longer life
“One of the exciting things is that reduced insulin activity contributes to healthy aging and longevity,” says Sander Liessem. This has already been shown in flies, mice, humans and other species. The same applies to an active lifestyle. “Our study provides a possible link to explain how physical activity positively affects insulin regulation via neuronal signaling pathways.”
Further steps in research
Next, Jan Ache’s team will investigate the neurotransmitters and neural circuits responsible for the observed activity changes in insulin-producing cells in flies. This will likely prove challenging. A large number of messenger substances and hormones are involved in neuromodulatory processes, and individual substances may have opposing or complementary effects in combination.
This group is currently analyzing the many ways insulin-producing cells process external inputs. They are also investigating other factors that may affect the activity of these cells, such as the fly’s age and nutritional status.
“In parallel, we are investigating the neuronal control of locomotion and flight behavior,” explains Jan Ache. His group’s long-term goal is to combine two of his research questions: how the brain controls locomotion and other behaviors, and how the nervous system adjusts energy balance accordingly. do?
Julius Maximilian University of Würzburg, JMU
Risem, S. and others. (2023) Behavioral state-dependent regulation of insulin-producing cells in Drosophila. current biology. doi.org/10.1016/j.cub.2022.12.005.