Biological complexity: complex glucose controls (Introduction)

by David Turell , Monday, November 14, 2016, 18:34 (2931 days ago) @ David Turell

Blood vessels produce chemical reactions that control glucose levels:

https://www.sciencedaily.com/releases/2016/11/161114103909.htm

Research led by a Johns Hopkins University biologist demonstrates the workings of a biochemical pathway that helps control glucose in the bloodstream, a development that could potentially lead to treatments for diabetes.

***

It has been known for some time that neurons and the pancreatic beta cells, or β-cells, that reside in clusters called islets of Langerhans and produce insulin, have many similarities in molecular makeup and signaling receptors. Receptors are proteins on cell surfaces that respond to particular chemicals and have critical roles in biochemical pathways. Both neurons and pancreatic β-cells have the receptors for neurotrophins. (my bold)

***

It turns out that NGF performs a function in the mature pancreas that has nothing to do with supporting neurons. Specifically, the research team traced a chain of biochemical signals showing that elevated blood glucose causes NGF to be released from blood vessels in the pancreas, and that the NGF signal then prompts pancreatic β-cells to relax their rigid cytoskeletal structure, releasing insulin granules into the blood stream. Although β-cells also make NGF, Kuruvilla and her team found that it was the NGF released from the blood vessels that is needed for insulin secretion. (my bold)

Using genetic manipulation in mice and drugs to block NGF signaling in β-cells, they were able to disrupt distinct elements of this signaling sequence, to show that this classical neuronal pathway is necessary to enhance insulin secretion and glucose tolerance in mice. Importantly, Kuruvilla and colleagues found that NGF's ability to enhance insulin secretion in response to high glucose also occurs in human β-cells.

Comment: This is another example of a system that cannot develop in small steps. It must appear all put together. Also look at the bolded portions describing how receptors receive information and how a chain of molecular reactions produce directions for results. All automatic, no thought involved.