Question

Describe where insulin in the brain comes from. (include references). (150 words)

Answer 1

Insulin is produced by the pancreatic beta cells in response to the increased blood sugar levels. Insulin is crucial in controling blood glucose level by helping to convert the surplus blood glucose into glycogen, a compound which can be stored in the liver cells and the muscles. In the brain, the insulin-independent GLUT 1 and GLUT 3 are mostly responsible for glucose uptake in the glial cells and neurons respectively while insulin helped to increase glucose uptake in several brain regions such as the choroid plexus, pineal gland and the pituitary, as well as the spinal cord tissue.

The secretion of insulin and other islet hormones are very much influenced by the hypothalamus and other brain areas and also, insulin action in the hypothalamus influences both energy balance and glucose metabolism.

Research suggests that insulin is also synthesized by some neurons in the cerebral cortex and the neural progenitor cells of hippocampus. This is done to offset the slow supply of insulin to the brain by pancreatic beta cells. The locally produced insulin in the brain provides a rapid means of regulating local microcircuits, effectively modulating synaptic transmissions and also helps to maintain energy homeostasis of neural networks.

Hence, it is widely believed by scientists that the source of insulin in the brain is not only from the beta-cells of the pancreas but also from some specialised neural cells.

Source - Cerebral Cortex: a target and source of insulin? by Eva A Csajbok and Gabor Tamas

[Published: May, 2016]

             Hypothalamic Regulation of Glucose-Stimulated Insulin Secretion by Owen Chan and Robert S Sherwin