Cycle and age influence insulin action and cognitive abilities in women
"Over the last few years, it has been shown that the brain is an insulin-sensitive organ, but also that a whole range of people do not respond to insulin in the brain," says Apl. Professor Dr. rer. nat. Stephanie Kullmann, Deputy Head of the Metabolic Neuroimaging Department at the Institute for Diabetes Research and Metabolic Diseases (IDM) at the Helmholtz Center Munich at the University of Tübingen.
They are referred to as insulin resistance of the brain: "This is particularly common in people with obesity, but differences between men and women also play a role," explains Professor Dr. med. Martin Heni, Head of the Endocrinology and Diabetology Section of the Department of Internal Medicine I at Ulm University Hospital. The two scientists will chair the German-Danish symposium "The brain's role in glucose metabolism" at the Diabetes Congress 2024 on Wednesday, May 8, 2024.
New research findings on young women indicate that their brain response to insulin varies depending on the phase of their cycle. In one study, 11 women with normalweight who were not using hormonal contraceptives were administered insulin as a nasal spray. This made it possible to selectively stimulate the insulin effect in the brain compared to a placebo nasal spray. The evaluation showed that after nasal insulin administration during the follicular phase, i.e. before ovulation, there was a higher insulin sensitivity in the body than during the luteal phase, i.e. the time after ovulation. "This is probably due to insulin resistance in this phase of the cycle," conclude Kullmann and Heni, who were both involved in the study. These results were confirmed by functional MRI scans in a further 15 women.
With increasing age, the effect of insulin in the brain decreases in women. This mainly affects limbic regions, explains Professor Kullmann: "Interestingly, the hippocampus in particular shows a decrease in insulin action in women after the age of 50, while the insulin action in the hippocampus in men does not change with increasing age between 20 and 70 years." The hippocampus is important for memory processes and is affected by Alzheimer's disease. Women develop Alzheimer's disease more often than men. "The latest data suggest that insulin resistance in the brain contributes to cognitive impairment, independently of whole-body insulin resistance," reports Martin Heni.
At the congress press conference on May 10, 2024, Stephanie Kullmann will explain the latest research findings on this topic.
Further information can be found on the DDG website.