Physical activity reduces the production of insulin


When a fruit fly starts walking or flying, its insulin-producing cells are immediately inhibited. This could be one explanation for why doing exercises promote health.

Electrophysiological measurements in active flies

The JMU group figured out that the physical activity of the fly has a strong effect on its insulin-producing cells. For the first time, the researchers measured the activity of these cells electrophysiologically in walking and flying Drosophila.

The result: when Drosophila starts to walk or fly, its insulin-producing cells are immediately inhibited y. When the fly stops moving, the activity of the cells rapidly increases again and shoots up above normal levels.

Blood sugar plays no role in the regulation

The JMU team was also able to demonstrate that the fast, behavior-dependent inhibition of insulin-producing cells is actively controlled by neural pathways. "It is largely independent of changes in the sugar concentration in the fly's blood," explains co-author Dr. Martina Held.

Further steps in the research

Next, Jan Ache's team plans to investigate which neurotransmitters and neuronal circuits are responsible for the activity changes observed in insulin-producing cells on the fly. This is likely going to be challenging: A plethora of messenger substances and hormones are involved in neuromodulatory processes, and individual substances can have opposite or complementary effects in combination.

The group is now analyzing the many ways in which insulin-producing cells process input from the outside. They are also investigating other factors that could have an influence on the activity of these cells, for example, the age of the fly or their nutritional state.

"In parallel, we are investigating the neuronal control of walking and flight behavior," explains Jan Ache. The long-term goal of his group, he says, is to bring these two research questions together: How does the brain control walking and other behaviors, and how does the nervous system ensure that the energy balance is regulated accordingly?