HWS 410: Carbohydrates in Health & Disease

Major organs that regulate blood glucose

Pancreas:

- 2 hormones: insulin, glucagon

Liver: glycogen breakdown

Insulin

lowers high blood sugar

Glucagon

raises low blood sugar

Liver

stores glucose in the form of glycogen and performs glycogen breakdown

What happens when blood sugar is high?

- high blood glucose

- sensed by pancreas

- insulin released by Beta cells of pancreas

- Fat cells take in glucose from blood

- Achieve normal blood glucose levels

What happens when blood sugar is low?

- low blood glucose

- sensed by pancreas

- glucagon release by Alpha cells of pancreas

- Liver releases glucose into blood

- Achieve normal blood glucose levels

Insulin is needed to open ________ _________, thus lowering blood sugar

glucose channels

Too much hormone outside of the cell leads to...

less receptors on the outside of the cell

Regulation of blood glucose levels: Insulin

Anabolic (building) response to hyperglycemia

- liver: stimulates glycogen synthesis, glycolysis, and fatty acid synthesis

- muscle: stimulates glycogen synthesis

- adipose: stimulates lipoprotein lipase resulting in uptake of fatty acids from lipoprotein (chylomicrons and VLDL)

Regulating of blood glucose levels: glucagon

Catabolic, in response to hypoglycemia

- liver: activates glycogen degradation, gluconeogenesis

- adipose: stimulates lipolysis and release of fatty acids

Insulin resistance pathway

- simple sugar -> favors store of fat in abdomen -> fat cell increases in size

- increase in cytokine release -> inflammation -> damaged insulin receptors -> insulin resistance

- cells not getting enough glucose -> breakdown of muscle and fat -> influx into liver

- liver -> resists insulin

- systemic insulin resistance

Increased glycation of body proteins

sugar attaching to body proteins (at a lysine residue)

- destroy their function

- aging (increase free radicals and inflammation)

sugar attaching to blood vessels (diabetes)

- heart disease, eye, kidney, skin Hb

- amputation of limbs

High fructose corn syrup

glucose and fructose are not attached so no digestion occurs; it's free so its quickly absorbed

Sucrose

glucose and fructose are attached to each other; fruits and honey have fructose NO glucose

Consequences of glycation

limited blood flow disturbs the normal response to wound healing and others

AGE deposition

advanced glycated end-products

- deposits in blood vessels and can contribute to atherosclerosis (narrowing of blood vessels)

- AGE can contribute to heart disease