Introducing the brain: special cells make insulin (Introduction)

by David Turell , Tuesday, June 17, 2025, 17:05 (10 days ago) @ David Turell

New research:

https://www.sciencealert.com/insulin-isnt-just-made-by-the-pancreas-heres-another-locat...

"Your brain makes insulin – the same insulin produced by your pancreas. The same insulin that is not produced in people with type 1 diabetes and the same insulin that does not work properly in people with type 2 diabetes.

***

"Insulin can and does move from the blood to the brain. But local sources of insulin are produced in specific places to do specific things.

***

"First, what is surprising about brain insulin production is that there is not one but at least six types of insulin-producing brain cell. Some have been confirmed in both rodent and human brain, others currently just in rodents.

"One of the first brain cells shown to make insulin is the neurogliaform cell. These live in a brain area important for learning and memory. Most surprisingly, the production of insulin here depends on the amount of glucose present – a feature shared with pancreatic beta cells.

"Its not clear what this insulin source does. Based on the location, it may contribute to cognitive function.

***

"...one insulin producing brain cell might regulate growth. A 2020 study showed that insulin is made and released from stress-sensing neurons in the mouse hypothalamus. This is a brain area that controls growth and metabolism. It also has the highest insulin levels in the human brain.

***

"Hypothalamic insulin maintained growth hormone levels in the pituitary gland. This is sometimes called the master gland as its involved in making or controlling production of other hormones. Having less local insulin meant less growth hormone production.

"Then there is the choroid plexus. This is the brain region that makes cerebrospinal fluid. In humans, that is about half a litre of this clear colourless liquid every day.

"Cells lining the choroid plexus – the epithelial cells – make a nourishing broth of growth factors and nutrients to keep the brain healthy. Only recently was insulin production found here in mice.

"The choroid plexus secretes fluid directly into brain ventricles, the spaces deep inside the brain. This fluid flows around the whole brain, perhaps delivering insulin more widely.

"One place it does travel to is the appetite control centre in the hypothalamus.

A 2023 study in mice showed that genetic control of insulin production by the choroid plexus could change food intake. The hypothalamus was rewired by changing choroid plexus insulin levels. Insulin released from here suppressed appetite.***

"There is still much to learn about brain insulin production. For example, which insulin source came first? The brain or the beta cell? Hopefully it doesn't take another 30 years to find out.

"But given the strength of evidence of brain insulin production, it won't be long until our school textbooks are updated."

Comment: since glucose is brain fuel it is logical that insulin is produced there to metabolize the glucose. It produces a fail-safe mechanism. The concept supports the design argument.