User:Honfaichan
From Wikipedia, the free encyclopedia
Insulin is an essential peptide hormone produced by beta cells in pancreas for regulating glucose homeostasis. The production of insulin occurs throughout the day and is stimulated after meals when large amount of glucose is generated from food digestion in a short time. The normal insulin profile found in blood would have a basal level throughout the day and spikes that are seen after meals. Insulin binds to insulin receptor located on insulin-responsive cells, primarily muscle and adipose cell, to activate an internal cellular mechanism that involves phosphorylation of cellular proteins and ultimately leads to an increase in glucose transporters (GLUT4) on the cell surface. An influx of glucose results and it is converted to glycogen, lipid for storage, or pyruvate for glycolysis [1]. Insulin binding also activates other cascades that lead to decrease in protein, lipid and glucose synthesis [2]. Consequently, the blood glucose level is reduced.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/0/0e/014-insulin-4ins.png/320px-014-insulin-4ins.png)