Structure:
Insulin, a hormone composed of 51 amino acids, is secreted by the beta
cells of the Islets of Langerhan. Before
it's release, insulin is stored as proinsulin, a polypeptide product that
is converted to insulin.
Function:
Insulin has hypoglycemic actions, reducing blood glucose quickly. It accomplishes
this by stimulating body cells to take up
glucose, signalling liver cells
to make glycogen from glucose (glycogenesis), and promoting glucagon
release from alpha cells in the Islets. Glucose is a humoral
transmitter for insulin's target tissues.
