145b Hypothalamic - anterior pituitary physiology Flashcards
endocrine vs nervous system - timeframe of signals
endocrine is slow, but long lasting with slower adaptation
posterior pituitary - aka? derived from? appearance on MRI?
neurohypophysis
neuroectoderm
bright on MRI
anterior pituitary - aka? derived from? what is superior to it?
adenohypophysis (Adeno = Anterior)
nasopharynx ectoderm (Rathke’s pouch)
optic chiasm
Does the hypothalamus secret hormones into portal veins for communication with the anterior or posterior pituitary?
anterior pituitary
What causes the circadian rhythms secretion of hormones? what does this affect?
SCN
affect - testing hormone levels is difficult so must use suppression/stimulation tests AND continuous hormone levels actually depress downstream secretions
what is the only pituitary hormones that is under tonic inhibition by a hypothalamus hormone?
which hypothalamus hormone does this?
Prolactin
Dopamine
Prolactin - source
anterior pituitary
prolactin - fxn
stimulates milk production
Inhibits GnRH synthesis and release thus inhibits ovulation/spermatogenesis
(remember that the body doesn’t want to ovulate while nursing so prevents another pregnancy too quickly)
Prolactin regulation
+ TRH and VIP (minor role)
+ estrogen (pregnancy/OCP)
+ dopamine antagonists (antipsychotics)
- dopamine (major)
- dopamine agonists (Bromocriptine; rx for prolactinoma)
growth hormone - source
anterior pituitary
growth hormone - fxn
linear growth at epiphyseal plate/muscle mass via IGF-1 (mostly from liver but also bone)
osteoclast, osteoblast differentiation
differentiation of procondrocytes
increases insulin resistance (diabetogenic) b/c its a stress hormones (wants to increase blood glucose for use by CNS)
Growth hormone - regulation
+ GHRH (pulsating) – increased during exercise and sleep
- somatostatin
- glucose
growth hormone - source
anterior pituitary
growth hormone - fxn
linear growth/muscle mass via IGF-1 (mostly from liver but also bone)
increases insulin resistance (diabetogenic) b/c its a stress hormones (wants to increase blood glucose for use by CNS)
Growth hormone - regulation
+ GHRH (pulsating) – increased during exercise and sleep
- somatostatin
- glucose
what does excess GH cause in adults? children?
acromegaly
gigantism
IGFBP - what are they? purpose?
IGF binding proteins
carry IGF in plasma
increase half life of IGF
what glycoprotein hormones share a structural subunit? which subunit?
TSH
FSH
LH
HCG
share alpha; beta give biological specifictiy
(“These Fucking Loser Hormones”)
what causes growth plate closure during puberty?
estrogen mostly
LH/FSH regulation
+ GnRH
-estrogen/progesterone, inhibin
what glycoprotein hormones share a structural subunit? which subunit?
TSH
FSH
LH
HCG
share alpha; beta give biological specifictiy
ACTH regulation
+ CRH, vasopressin
- cortisol (Feedback)
LH/FSH regulation
+ GnRH
-estrogen/progesterone, inhibin
What is ACTH synthesized from? what else is made?
POMC
makes MSH (tanning) too
