Physiological actions of insulin

Liver

Glucose

Liver

Glucose

Glucagon

FIGURE 1.1 Actions of insulin and glucagon on hepatic glucose output.

Glucagon

Pancreas

FIGURE 1.1 Actions of insulin and glucagon on hepatic glucose output.

and liver as a fuel source, thus reserving the supply of glucose as a fuel for other tissues, e.g., brain. During prolonged fasting, fatty acids may also be metabolized by the liver to form ketone bodies. Although the liver cannot use ketone bodies as a fuel source, other tissues are able to utilize them and they may become a major source of fuel in prolonged starvation.

Insulin Action on Protein Metabolism

Average protein turnover in a well-fed man is estimated to be 250 to 300 g daily — much greater than the average intake of protein of 75 to 100 g — so turnover of endogenous proteins accounts for the majority of daily protein turnover. Overall insulin has an anabolic action on protein turnover. In vivo studies suggest that the main effect of insulin appears to be a reduction in protein breakdown (proteolysis) in muscle and liver rather than a stimulation of protein synthesis.34 In the insulin deficiency of diabetes, lack of insulin action on protein degradation contributes to weight loss by catabolism of lean tissue.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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