L10 Flashcards
growth factor (62 cards)
what type of hormone is growth hormone?
polypeptide
growth hormone action is mediated by _____
IGF-1
what kind of receptor does GH use?
cytokine receptor
GH is stimulated by _____ and inhibited by _____
GHRH; somatostatin
GH is released by what kind of cell?
somatotrophs in the anterior pituitary
growth hormone is in the same family as _____
prolactin
what type of hormone is prolactin and what does it do?
protein hormone. it regulates breast milk production and lactation in women.
true or false: growth hormone has growth-promoting activity as well as weak prolactin-like lactogenic activity
true
true or false: prolactin has lactogenic activity and growth-promoting activity
false; prolactin has NO growth-promoting activity
Placental lactogen has [strong/weak] lactogenic activity, and [strong/weak] growth-promoting activity
strong; weak
Human placental lactogen is also called ______
human chorionic somatomammotropin (HCS).
factor that inhibits GH secretion
elevated glucose
factors that promote GH secretion
hypoglycemia, exercise, amino acids
true or false: IGF-1 stimulates somatostatin
true
GH is released in a [pulsatile/steady] manner
pulsatile
mechanism of releasing GH
GHRH activates GPCR on anterior pituitary somatotrophs –> adenylate cyclase and PLC –> production of GH and release of GH in vesicles (exocytosis stimulated by Ca)
Actions of growth hormone
Anabolic and Anti-catabolic actions, Increasing protein synthesis, increases FA oxidation, decreasing protein catabolism
what response do all somatostatin receptors cause?
inhibition of adenylyl cyclase
factors stimulating GH (8)
hypoglycemia, protein-rich diet, higher amino acids in blood, exercise, stress, sleep, glucagon, ghrelin
factors inhibiting GH (4)
hyperglycemia, free fatty acids, GH negative feedback of secretion, cortisol excess
IGF-1-dependent effects
protein synthesis, AA transport, muscle mass, bone growth, cartilage growth, nucleic acid synthesis
IGF-1 independent effects
anti-insulin, lipolysis, ketogenesis, hyperglycemia, Na and water retention
Growth Hormone direct effects
stimulates growth (hypertrophy), stimulates cell reproduction (hyperplasia), stimulates cell metabolism (protein synthesis, fat breakdown for energy, glycogen breakdown)
GH stimulates secretion of what hormone(s)?
IGF-1 and IGF-2