Biochem 2: pit and hypo Flashcards
Describe hypophysiotropic hormones
hormones derived from the hypothal and enters the portal system and act on the ANTERIOR PITUITARY
what is another word for hypohysiotropic hormones
“releasing hormones”
Where are hypophysiotropic hormones produced
- arcuate nucleus
- paraventricular nucleus
- anterior periventricular nucleus
- supraoptic nucleus
What type of hormone is hypophysiotropic hormone
peptide hormone released as pre-prohormone
Describe adenohypophysis hormones
hormones secreted from anterior pit. Usually in response to releasing hormones from hypothal
What type of hormone is adenohypophysis
peptide hormones
What type of tissue is anterior pit from
Ectoderm tissue
name a few adenohypophysis hormones
TSH, ACTH, FSH and LH, GH, prolactin, endorphins
Describe neurohypophysis hormones
made in the hypothal and goes into the general circulation via the posterior pit.
What type of tissue is posterior from
neural tissue and an extension of the hypothal
name 2 neurohypophysis hormone
ADH and oxytocin
Synthesis of PRL , an ant. pit. hormones occurs in the ant. pit in the absence of inhibitory tone; TRUE or FALSE
TRUE
and also in response to releasing hormone (PRH)
What do somatotrophs secrete? what stimulates it? What inhibits it? where does it target?
GH
GHRH - stimulates
Somatostatin - inhibits
Targets: bones, soft tissue, entire body
What do lactotrophs secrete? what stimulates it? What inhibits it? where does it target?
Prolactin
PRH - stimulates
Dopamine - inhibits
Targets: mammary glands
What do thyrotrophs secrete? what stimulates it? where does it target?
TSH
TRH - stimulates
Targets: Thyroid
What do corticotrophs secrete? what stimulates it? where does it target?
ACTH
CRH - stimulates
Targets: Adrenal cortex
What do gonadotrophs secrete? what stimulates it? where does it target?
FSH and LH
GnRH - stimulates
Targets: Testes or Ovaries
post. pit. hormone is secreted into …
and out into …
the general circulation
the blood stream
oxytocin is released in response to …
uterine birth –> contraction or breast feeding –> the smooth muscles contract around the mammary gland
ADH is released in response to …
hyperosmolaity, fluid depletion, and thrist
All hypophysiotrophic hormones are peptide hormones except,…
Dopamine
its a catecholamine made from tyrosine (aa hormone)
Hypophysiotrophic hormone that goes to the post. pit are made from what cells in the hypothal
Magnocellular cells
Both oxytocin adn ADH have what types of bonds
disulfide bonds
Are the genes for vasopressin and oxytocin on the same chromosome
YES they are
Oxytocin is produced on the same protein sequence as …
neurophysin I
What happens to both neurophysin I and oxytocin
splicing cleaves the two proteins to their active form
They are secreted together
Often thought that neurophysin I is a carrier protein for oxytocin
Where is vasopressin transcribed from
the same mRNA as neurophysin II
What happens to both vasopressin and neurophysin II
cleavage splits the 2 proteins to their active form
Neurophysin II is thought to be the carrier protein of ADH
What receptor and where does ADH target?
V1 receptor (vascular) - V2 recptor (renal)
what happens when ADH targets V1 receptor
binds to Gq –> smooth muscle constriction (in vasculature) –> increased blood pressure
Gq (PLC, IP3/DAG, PKC, Ca2+)
when ADH targets V1 receptor what effect is triggered
cellular effect
what happens when ADH targets V2 receptor
binds to Gs –> up-regulation of aquaporins in the kidney –> increases water reabsorption
Gs (AC, cAMP, PKA)
when ADH targets V2 receptor what effect is triggered
genomic effect
What receptor and where does oxytocin target?
binds to OXYTOCIN RECEPTOR in UTERUS smooth muscle and MAMMARY smooth muscle
How does the oxytocin receptor work
works through Gq –> contraction of smooth muscles
mammary –> milk ejection
uterus –>contraction during birth
What receptor and where does GH target?
binds to GH receptors in BONE, TISSUE, MUSCLES, etc…
How does the GH receptor work
works through JAK/STAT receptor –> STAT translocates to the nucleus –> regulates gene related to METABOLISM, growth, and differenitation
what happens when ADH targets V2 receptor
binds to Gs –> up-regulation of aquaporins in the kidney –> increases water reabsorption
Gs (AC, cAMP, PKA)
when ADH targets V2 receptor what effect is triggered
genomic effect
What receptor and where does oxytocin target?
binds to oxytocin receptor in uterus smooth muscle and mammary smooth muscle
How does the oxytocin receptor work
works through Gq –> contraction of smooth muscles
mammary –> milk ejection
uterus –>contraction during birth
What receptor and where does GH target?
binds to GH receptors in BONE, TISSUE, MUSCLES, etc…
How does the GH receptor work
works through JAK/STAT receptor –> STAT translocates to the nucleus –> regulates gene related to METABOLISM, growth, and differenitation
the GH receptor as a result increases…
blood glucose, lipolysis, (possibly protein synthesis/AA uptake)
What is IGF-1
- its created in the liver in response to GH activation
- induces cellular growth and proliferation more than GH
- allows cells to utlize the energy rich molecules in blood that are released by GH
IGF-1 as a result increases and decreases what
increases: glucose uptake into extrahepatic tissue, AA uptake, and protein synthese
decreases: lipolysis
what is unique about IGF-1
inhibitory to GH release
opposes the actions of GH
What receptor and where does prolactin target?
binds to prolactin receptor in MAMMARY glands
How does the Prolactin receptor work
works throught the JAK/STAT receptor (receptor dimerization) –> activates genes that are important in milk production (post partum) and for breast development (estrogen primed breast not puberty boobs)
GH secretion peaks at … and/or in response to…
peaks at night
low energy states
Abnormal hyper secretion of GH is due to 2 phenomena
- GH adenoma
2. insensitivity of GHReceptors to GH
What 2 conditions develop due to GH adenoma
- gigantism in CHILDREN (before growth plates fuse)
2. acromegaly in ADULTS (growth of soft tissues and facies after growth plates fuse)
What happens in insensitivity of GHR to GH
there no feedback of IGF-1 to turn off the system bc there is no genomic effect with defective receptors (which leads to high GH concentration) –> Laron Dwarfism
what do GH and PRH have in common
the signaling pathway- JAK/STAT
TRUE or FALSE: JAK is phosphorylated upon binding of GH/PRL
TRUE
dimerizes in PRL, may in GH
What else can be activated in the JAK/STAT cascade
MAP kinase
have an effect of proliferation by phosphorylating target proteins (genomic or cellular effect)
what is POMC
Pro-opionmelanocortin
pre-prohormone
POMC is modified to make…
ACTH, LPH, MSH
pathway of POMC
POMC cleaved to:
- Pro-ACTH –>ACTH –> ACTH1-17 –> alphaMSH
- Pro-LPH –> B-LPH –> betaMSH
WHat does the pineal gland secrete?
Melatonin
where does melatonin derive from
Tryptophan
Melatonin’s function
antioxidant and involved in the circadian rhythm
CALCIFIED overtime
production decreases as you age
