What is the function of endrogenous insulin?

Endogenous insulin is produced by the beta cells of the pancreas and plays a crucial role in regulating glucose metabolism in the body. Here are the main functions of endogenous insulin:

1. Glucose Transport:

- Insulin facilitates the transport of glucose from the bloodstream into various tissues, primarily muscle, fat, and liver cells.

- By increasing glucose uptake, insulin helps lower blood glucose levels.

- Insulin-responsive cells have specialized glucose transporters, such as GLUT4, that are recruited to the cell membrane in response to insulin, enhancing glucose uptake.

2. Glycogen Synthesis (Glycogenesis):

- In muscle and liver cells, insulin promotes the synthesis and storage of glucose as glycogen.

- After a meal, when blood glucose levels rise, insulin signals the cells to convert excess glucose into glycogen through a process known as glycogenesis.

3. Lipogenesis and Fat Storage:

- Insulin stimulates the synthesis and storage of triglycerides in adipose tissue (fat cells).

- When insulin levels are high, fatty acids are taken up by fat cells and converted into triglycerides for energy storage.

4. Protein Synthesis:

- Insulin promotes protein synthesis and inhibits protein breakdown.

- Adequate insulin levels are essential for muscle growth and repair.

5. Suppression of Gluconeogenesis and Glycogenolysis:

- Insulin suppresses the production of glucose in the liver (gluconeogenesis) and the breakdown of stored glycogen (glycogenolysis).

- This helps prevent the overproduction of glucose when insulin levels are normal or elevated.

6. Regulation of Ketogenesis:

- In the liver, insulin inhibits ketogenesis, the production of ketone bodies.

- Ketone bodies are alternative fuels produced when glucose is scarce, but insulin's presence signals sufficient glucose availability, reducing ketogenesis.

Overall, endogenous insulin acts as a key hormone in maintaining glucose homeostasis by regulating glucose uptake, storage, and utilization in different tissues. Its primary function is to ensure that cells have adequate glucose for energy production and storage, while preventing excessive glucose build-up in the bloodstream.