ENDO Week 6 Flashcards
(48 cards)
what hormone class is GH? which pathway does it use?
protein hormone
acts through the JAKSTAT **(tyrosine kinase) binding site
o no second messenger
o dimerization** occurs for receptor activation
how does it travel in the blood
50% in bound form
where are some of growth hormones receptors located
in the blood as well as target tissues
what other hormones are involved in growth
TH, androgens, estrogen, cortisol, insulin
what are some actions of GH
Increase protein synthesis
Decreased protein catabolism
Increases lipolysis
Increases blood glucose level
what effect does GH have on BP
increases GH = increased BP
what are the effects of GH on protein metabolism
o Increased rate of protein synthesis **
o Decreased protein catabolism
what are the effects of GH on lipid metabolism
o Increased free fatty acids in the blood
o Increased use of fatty acids for energy, breakdown of fat, lipolytic
o Can be ketogenic after long term release of GH
what are the effects of GH on carbohydrate metabolism
o GH causes insulin resistance and decreases glucose uptake
increases blood glucose
o Decreased rate of glucose utilization throughout the body
o Increase hepatic output of glucose
what role does insulin play in growth
insulin is increased with GH release because they work synergistically for growth
what is the effect of GH on insulin
GH increases insulin secretion and reduces its action
GH= hyperglycaemic
insulin= hypoglycaemic
why is GH considered a diabetogenic hormone
excess GH = hyperglycaemia and diabetes mellitus
GH’s antagonistic actions of insulin
GH increases BG by inhibiting glucose uptake
GH effect on bone and cartilage
Increases number of chondrocytes
causes proliferation of chondrocytes
chondrocyte deposition
increase bone formation from osteoblasts
what effect does GH have on the receptors of chondrocytes
increases receptors for IGF-1 on chondrocytes
when does linear growth stop
Once bone grows from epiphyseal plate and fuses with epiphysis
what kind of hormone is IGF-1 (somatomedin C) and where is it secreted from
a protein hormone
secreted from liver mainly (also cartilage)
what does GH stimulate the liver to do?
stimulates IGF -1 production
how does IGF-1 secretion change from before and after birth
before birth: IGF-1 secretion is independent of GH
after birth: IGF -1 secretion is stimulated by GH
how is IGF-1 transported in blood
bound form
what protein does IGF-1 bind to
IGF binding protein 3 (IGFBP3)
what receptor pathway does IGF -1 use?
Tyrosine kinase receptor
what is the action of IGF -1
same as GH
does IGF -1 cause hypoglycaemia like insulin?
no
where is IGF-2 (somatomedin A) secreted from and what is its function
secreted from placenta and fetal liver
major role for fetal growth
