Role of insulin and glucagon in metabolism

insulin

peptide hormone produced by B-cells of pancreas that does anabolism

how does glucose enter the B-cells of the pancreas

Glut-2 transporters

where are GLUT-2 transporters located

liver, pancreas, and small intestine

what stimulates insulin release

arginine and leucine, CCK, GLP-1, G-1-P

what inhibits insulin release

norepinephrine → increase in serum glucose

where are GLUT-4 transporters

skeletal, cardiac, and adipose tissues

what kind of diffusion does GLUT-4 transporters participate in

facilitated diffusion

what kind of action does GLUT-4 do to bring glucose into the cell

uses vesicles to fuse with the plasma membrane allowing glucose to move into the cell

what does insulin promote in regards to lipids

lipid storage increases triglyceride synth, adipocytes absorb more fatty acids circulating in the blood, inhibits lipolysis

what does insulin do in regard to protein metabolism

prevents proteolysis, absorbs amino acids to build new protein

DM1

cannot produce insulin, immune system destroys pancreatic B-cells

DM2

cells gradually lose their ability to respond to insulin (insulin resistance)

glucagon

peptide hormone by pancreatic alpha cells; does catabolism

what are the target tissues of glucagon

liver, skeletal muscle, kidney, heart, brain

what kind of receptors bind to glucagon

they are a type of GPCR

what stimulates glucagon

stress hormones (norepinephrine, epinephrine, cortisol)

what does glucagon do

increases blood sugar through glycogenolysis and glyconeogenesis

what does glucagon stim in terms of lipid metabolism

lipid catabolism via stress hormones

how is glycerol hydrolyzed into FFA

glucagon activates protein kinase A sensitive lipases in adipose tissues

what does glucagon do in terms of protein metabolism

it inhibits protein synthesis and allows for proteolysis; a.a. can be sent to the liver to make new glucose molecules in gluconeogenesis