Hormones Controlling Plasma Nutrients Flashcards
What tissues does insulin cause glucose to go into?
Skeletal muscle, the liver and adipocytes
How does insulin reduce the hepatic glucose output?
By stimulating glycogen synthesis and inhibiting glycogenolysis (the breakdown of glycogen)
What does insulin do the the amino acids in the plasma?
Stimulates their incorportation into proteins in the muscle and fatty acids in the liver
What does insulin causing increased uptake of amino acids and glucose by the liver lead to?
Conversion to fatty acids and then to lipoproteins which are released into the blood
Where do the lipoproteins go once released into the blood? What action causes this?
To adipocytes through lipoprotein lipase action
What does insulin cause glucose oxidation to?
Fatty acids which are stored as triglycerides (lypolysis prevented)
What are the three long term effects caused by insulin
- Fatty acids into adipocyte store
- Glucose into glycogen or adipocyte fat
- Amino acids into protein or fatty acids
What cells have the receptors to sense glucose changes?
B-cells in the pancreatic islets
What happens to stimulate insulin secretion from the B-cells in the pancreatic islets
Calcium ions rush into the cell causing insulin release
What does oral glucose do to change insulin levels?
Effects the levels via GIP
What does a rise in amino acids do?
Increases release
What does the sympathetic nervous system do the insulin secretion?
Inhibits it
What does the parasympathetic nervous system do the insulin secretion?
Increase it
What does somatostatin do the insulin secretion?
Inhibits it
What does a rise in glucagon levels do the insulin secretion?
Stimulate the release
What are ketone bodies?
They are produced from the liver during prolonged fasting
What do ketone bodies do to insulin secretion?
They stimulate it
Where is glucagon secreted from?
alpha-cells in the islets
What are the four action of glucagon?
- Adipocyte lipolysis
- Liver gluconegogenesis
- Liver glycogenolysis
- Liver ketone synthesis
What does adipocyte lipolysis by glucagon cause?
Fatty acids and glycerol production
What does liver gluconeogenesis and glyconeogensis cause?
The breakdown of proteins and glycogen into glucose
What are ketones?
Small molecules derived from fatty acids that will enter the TCA when proteins are broken down
What does insulin do to glucagon release?
Inhibits it
What does low blood glucose levels do to glucagon release?
Stimulates it
What does increased amino acids concentrations do to glucagon release?
It increases it
Why is glucagon released when insulin is released in high concentrations of amino acids?
Glucagon counteracts the hypoglycemia during amino acid uptake
What do amino acids in the intestinal luman do?
Cause CCK release
What does CCK do?
Stimulates glucagon release
What does increased sympathetic stimulation do the glucagon release?
Increases it
What does an increase in plasma adrenaline do to glucagon release?
increases it
What are the 6 effects of sympathetic stimulation with adrenaline
- Glucogen breakdown to lactate
- Liver gluconeogensis
- Liver glyconeolysis
- Liver lipolysis
- Inhibition of insulin release
- Activation of glucagon release
How does cortisol affect insulin?
It antagonises it in the periphery
When do plasma levels of cortisol rise?
Under physiological stress
What is the effect of growth hormone?
- Increases adipocyte sensitivity to adrenaline in order for it to be broken down
- Increases liver gluconeogensis
- Reduces the effect of insulin
What is the overall effect of cortisol?
Permits the rise in plasma glucose and fatty acids caused by other hormones
What is the overall effect of growth hormone
Increased plasma glucose and fatty acids concentrations
