http://en.wikipedia.org/wiki/Image:Insulincrystals.jpg

• Organic compounds• Large complex molecule made up of

1 or more chains of amino acids• Perform wide variety of activities in

cell

• 1869: Paul Langerhans studied structure of pancreas– Noticed unidentified cells in

exocrine tissue (Islets of Langerhans)

• 1889: Oscar Minkowski removed pancreas from dog & found sugar in dog’s urine– Demonstrated relationship between

pancreas & diabetes

• 1901: Eugene Opie discovered link between Islets of Langerhans & diabetes– Diabetes mellitus… is caused by

destruction of the islets of LAngerhans and occurs only when these bodies are in part of wholly destroyed.

• 1922: VICTORY! Insulin officially discovered by Frederick Banting & Charles Best

• After digestion, when blood is filled with glucose, pancreas releases insulin into bloodstream

• If blood is extremely saturated with glucose, insulin inside liver stores excess glucose as glycogen

• After digestion, when blood is filled with glucose, pancreas releases insulin into bloodstream

• If blood is extremely saturated with glucose, insulin inside liver stores excess glucose as glycogen

• Increased production of fatty acids – forces adipose tissue to make fats from fatty acids

• Decreased proteinolysis – reduction of protein degradation

• Decreased lipolysis – reduction in conversion of fat cell lipid stores into blood fatty acids

• Controls degradation of proteins in cells

• Stimulates cells to absorb amino acids circulating in blood

• Increase of DNA replication & protein synthesis via control of amino acid uptake

• Secreted in beta cells• Islets of Langerhans• Pancreas, located in abdomen

• Two polypeptide chains: alpha chain & beta chain

• 21 amino acids long

• 30 amino acids long

• Connected by 2 disulfide bonds– Forming globular

shape

• Amino acid sequence differs slightly between vertebrates– Allows pig or bovine insulin to be

injected into humans & still function normally

• Binds to plasma membrane of adipose, muscle, & other cells

• Triggers other subunit of receptor to signal vesicles with GLUT-4 glucose transporters to fuse with membrane

• Transporters recognize & bind to glucose molecules– Facilitate selective intake of glucose

• Type 1 Diabetes: produce no natural insulin– Rely on insulin shots

• Type 2 Diabetes: body cells react sluggishly to insulin– Blood sugar levels rise dramatically after

meals

• http://www.endocrineweb.com/diabetes/2insulin.html

• http://en.wikipedia.org/wiki/Insulin#Discovery_and_characterization

• http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/pancreas/insulin_struct.html