Growth Hormone Flashcards
describe the signal transduction of growth hormone
ligand binding to receptor
this causes the cytoplasmic domain of the receptor to recruit JAK and phosphorylation occurs
several intracellular proteins dock including SH domains
other cellular proteins phosphorylated leading to a celluar response
role of GnRH
growth hormone releasing factor
made by hypothalamus to stimulate the ant pit to make GH
what is GH
a mitogen peptide
necessary for the maintenance of good health in adults and growth in children
effects of GH
indirect: - liver to stimulate secretion of IGF-1 to stimulate bone groth - muscle to stimulate proteiin synthesis direct: - opposes insulin
cellular response to GH singallin
STAT causes transicptional activiation
direct actions of GH
antagonist for insulin diabetogenic decreases glucose into cells increases plasma glucose increased plasma fatty acids
laron syndrome
serum GH too high but receptors non functional due to gene mutation
leads to small stature
what type of hormone is GH
a single polpeptide chain
what mediates the indirect actions of GH
IGF-1 which that then promote the …
- linear bone growth
- protein synthesise
- growth of soft tissues
hypopituitaryism
too little GH secreton in childhood
leads to dwarfism
excess GH due to GH secreting pituitary tumour
gigantism in young chidren
or
acromegaly in adults
what is acromegaly
thickening of bones and soft tissues, coarsening of features due to too much GH
GH deficiency
dwarfism. stunted growth
how is acromegaly treted
reduce excess GH
- remove tumour surgically
- radiotherapy to arrest the tumour growth
- stomatastin analogue to reduce the GH secretion
adult growth hormone deficiency
clnical syndrome body doesnt produce enough GH leading to metabolic effects in the body - raised lipids - reduced muscle strength - weak bones - low energy capacity - depression
