Insulin and glucagon

after a meal, insulin and glucagon

Insulin would increase and glucagon would decrease.

insulin

stores glucogen, fat and protein, decreases plasma glucose, amino acids and fatty acids

when insulin decreases and glucagon increases,

hydrolysis of glycogen, fat and protein, gluconeogenesis, plasma glucose rises, amino acids and fatty acids too

glucagon and insulin are released from

pancreas and have opposite effects

insulin uptakes and stores

glucose and FFA

insulin plasma concentration _______________ during exercise

decreases

decreased insulin response following

training

glucagon mobilizes

glucose and FFA fuels

glucagon plasma concentration __________ during exercise

increases

decreased glucagon response following

training

insulin and glucagon secretion influenced by

catecholamines

with exercise and training, there is an improved

counter regulatory control of insulin and glucagon

what does improved counter regulatory control of insulin and glucagon mean?

- able to maintain homeostasis better

- don't have to secrete as much to have a sufficient effect

- there won't be big spikes and dips

in endurance trained athletes

- decreased glucose uptake by muscle (need for glucagon decreases, less glucagon releases glucose)

- increased glucagon sensitivity at liver

- increased glucagon receptor density at liver

- increase in muscle's use of fat as a fuel

as percent VO2 max increases, insulin

decreases then increases again at a high intensity

in trained athletes, plasma insulin

does not decrease quite as much

muscle uptake of glucose during exercise is

7-20 x HIGHER (thats a lot)

Why is muscle uptake of glucose 7-20X higher??

increase in blood flow to muscle during exercise, more receptors are being exposed to glucose.

glucose delivery is the product of

muscle blood flow and the blood glucose concentration

Glucagon changes during exercise

adaptations due to training that involve receptor DENSITY, sensitivity and utilization of substrates

In TRAINED subjects, what happens to plasma glucagon

it basically does not change, as compared to untrained subjects who show a large increase. (basically your when your body is not used to exercise, it dumps a bunch of glucagon into your blood to free up fuel)