20 - Growth Hormone Flashcards
What hormone promotes increased size of cells and mitosis?
Growth hormones, Somatotropic hormones
What reglatues hGH
GHRH and GHIH controls hGH
Through what mechanism does GHRH use to release GH
act A.C to inc cAMP which: Inc ca transport into cells
and
Inc transcription in nucleus
What action does Somatostaine have?
It inhibits A.C .. reducing synthesis/amount of GH
What are the 3 negatives loops controllling GH
I-GHRH-Somatostatin aka ultrafast circuit
II-SS release
III- IGF-1 (long circuit) inhibits GH secretion and GHRH release
What evidence is there for negative feedback loop of GH?
If you administter more then u need, you see a GH decrease secretion
What does GH secreiton look like?
Its rhythmic ad pulsating . for every peak GH = Inc of GHRH = Dec of somatostatin
and a peak of somatostain = dec secretion of GH/ GHRH
What can stimulate GH secretion?
Low levels of glucose Starvation Exercising Ghrelin High amino acids levels or Low fatty acid levels GHRH
How is GH transported?
Using Ghrowth Hormone Binding proteins
its eliminated in kidney
What forms of Gh-R exist?
Full-length membrane membrane bound
and
GHBP (short version)
Does G.H work have specificity ?
no, they don’t function through target gland but exerts effects on all the body
Describe the kind of growth you would see if you injected a rat with GH?
Until adulthood everythin is proportional, but once the bones stop growing, then its just the soft tissue that you see an increase in
What can GH do to metabolism:
Inc. body protein , Use up fat stores more and Decrease the amount of glucose used.. aka increases conservation
How is GH similar to insulin?
GH enhance transport of A.A through the cell membrane.. Kinda like insulin would in bringing glucose inside
What can GH do in relation to RNA..
It can promote the RNA transcription in the nucleus.. = inc proteins
but also Inc the translation =in the cytoplasm
