Anterior Pituitary and Growth Hormone Flashcards
(18 cards)
Where is growth hormone produced?
By the anterior pituitary
What regulates the release of growth hormone?
The hypothalamus through GHRH and GHIH
What stimulates GHRH release from the hypothalamus?
Low blood glucose
What five factors increase GH secretion?
- Stress
- Exercise
- Fasting
- High protein intake
- Sleep
What type of molecule is growth hormone?
191-amino-acid polypeptide
What does the hormone receptor concentration determine?
Hormone sensitivity
What are the primary metabolic effects of GH on protein metabolism?
- Increased nitrogen retention
- Amino acid uptake
- Protein synthesis via IGF-1
How does Gh affect carbohydrate metabolism during low energy states?
- Promotes lipolysis
- Inhibits glucose uptake
- Raises blood glucose levels
What can long term GH administration lead to regarding glucose metabolism?
- Persistent hyperglycaemia
- Overstimulation of insulin
- Potential pancreatic exhaustion
How does Gh act when glucose levels are normal?
Promotes glucose and amino acid uptake for protein synthesis
What is the action of GH in the liver?
- Increased RNA and glucose synthesis
- IGF production
What is the action of GH in muscle?
- Increased AA uptake and protein synthesis
- Decreased glucose uptake
What is the action of GH in adipose tissue?
- Decreased glucose uptake
- Increased lipolysis
How does GH promote energy efficiency?
By sparing glucose and amino acids for growth and directing fat metabolism for energy
What is the role of GH in bone growth?
Stimulates cartilage cell mitosis
How is GH used in dairy cows?
Recombinant BST slows mammary cell decline and boosts nutrient deliver to extend peak milk production
What three hormones work with GH to support growth?
- Insulin
- Gluccocorticoids
- Thyroxine
What is acromegaly and what causes it?
Excess GH after maturation leading to cartilage overgrowth and tissue thickening
