Insulin Production in the Brain: A Surprising Fact Challenging Traditional Views

Insulin in the Brain: Beyond the Pancreas

Contrary to what many have learned, insulin production is not exclusive to the pancreas. Recent discoveries reveal that the brain itself synthesizes insulin, a fact that fundamentally alters our understanding of this vital hormone.

Historically, scientists have focused on the pancreatic beta cells as the sole source of insulin, essential for regulating blood sugar levels. However, over the past few decades, evidence has accumulated indicating that the brain not only responds to insulin but also produces it locally. This knowledge stems from studies dating back to the late 1970s, where insulin levels in the rat brain were found to be significantly higher than in plasma, suggesting local synthesis.

Initial research in the 1980s attributed brain insulin to transfer from the blood, as earlier methods couldn't detect insulin synthesis within brain tissue. But newer techniques have confirmed the presence of at least six different types of insulin-producing cells in the brain, some of which are found in both rodents and humans.

One of the key brain cells capable of producing insulin includes neurogliaform cells, which are located in regions linked to learning and memory. Interestingly, insulin production in these cells depends on glucose levels—a characteristic sharing similarities with pancreatic beta cells. Additionally, neural progenitors, which are capable of generating new neurons, also produce insulin, hinting at roles in neuroplasticity and brain health.

Other insulin-producing sources include the olfactory bulb, the hypothalamus, and the choroid plexus. The hypothalamus, a brain area crucial for regulating growth and metabolism, synthesizes insulin in response to stress, influencing growth hormone levels and overall growth. The choroid plexus, responsible for producing cerebrospinal fluid, produces insulin that circulates through brain ventricles, potentially affecting appetite regulation centers like the hypothalamus.

Moreover, insulin in the brain isn't solely about local production. It appears to play significant roles in maintaining cognitive function and preventing neurodegenerative diseases. For instance, in Alzheimer’s disease, the brain shows signs of insulin resistance, which affects glucose utilization—a condition sometimes referred to as "type 3 diabetes." This has prompted research into intranasal insulin therapies aimed at improving cognitive performance and slowing disease progression.

Interestingly, higher insulin levels in cerebrospinal fluid have also been linked to poorer cognition in women, indicating that the relationship isn't straightforward.

Overall, these findings underscore the importance of local insulin production in the brain. As research progresses, our understanding of its functions and implications for neurodegenerative diseases could lead to new, innovative treatment approaches.

Source: https://medicalxpress.com/news/2025-06-school-insulin-isnt-pancreas.html