Insulin

Insulin is a humorally regulated hormone. It is widely believed that insulin synthesis and release mainly from the pancreatic beta cells in response to blood glucose levels. Insulin is initially synthesized as preproinsulin and removal of its amino terminal single peptide generates proinsulin. Excision of C peptide within the endoplasmic reticulum, give rise to α (21 amino acids) and β (30 amino acids) of insulin. C peptide is a biomarker of insulin secretion. Various factors may influence insulin secretion. One of the key factors is blood glucose level. When glucose concentration rise, glucose move into the cell by a glucose transport. Then, glucose metabolized to generate ATP, which blocks ATP- dependent K+ channels in the b-cell membrane,