fuel homeostasis Flashcards
what is the postabsorptive state?
when the GI tract is empty and energy is supplied by body stores. normally occues late morning and afternoon, all night.
what is the absorptive state?
when ingested nutrients are entering the blood from the GI tract - 3 hours for an average meal
organs involved in fuel homeostasis?
liver - major glucogen store
adipose - triacylglycerol store
muscle - majority of body mass so major consumer of fuel
absorptive state: glucose
liver has a net uptake of glucose which is converted to glyocgen for storage
the muscle uses glucose for energy
adipose - glucose converted to fatty acids and a-glycerol phosphate which is essential for TAG synthesis in adipocytes
absorptive state: amino acids
liver - converted to keto acids, enter TCA cycle, or converted to fatty acids
skeletal muscle - used to synthesise proteins lost by catabolism
absorptive state: triacylglycerols
adipose - fatty acids converted to TAG by combining with a-GP `
What stimulates insulin release?
increased blood glucose in absorptive state.
how does insulin increase anabolic actions?
increases glucose uptake, activates glycogen synthase
how does insulin decrease catabolic actions?
inhibits gluconeogenesis, ketone production, adipocyte liplysis. reduces glycogenolysis in liver and muscle
Where is cortisol produced?
adrenal cortex
what does cortisol do?
maintains liver and adipose enzymes required for glucogenesis and lipolysis
cortisol deficiency results in?
addison’s disease
excess cortisol results in?
cushing’s disease - opposes effects of insulin
where is growth hormone produced?
anterior pituitary under the control of hypothalamus
what does growth hormone do?
makes adipose more sensitive to lipolytic stimuli and increases gluconeogenesis in the liver.
