Pituitary, Receptors, ADH Flashcards
Order of acquired loss of anterior pituitary function
GH, LH/FSH, TSH, ACTH, and PRL.
Go look for the anterior pituitary
Go look for the adenoma please
Causes of hypopituitarism
9 I’s
Invasic
Idiopathic
Infection
Infiltrative
Infarction
Injury
Immunologic
Iatrogenic
Isolated
Hypothalamus comes from what 2 neurons
Hypophyseotropic neurons
PVN & Arcuate N
(ant pit)
Magnocellular neurons
PVN and SON
(post pit)
how is ant pit formed
Invagination of Rathke’s Pouch (ectoderm)
what is Pars Intermedia
boundary between anterior & posterior – remnant of Rathke’s Pouch
how is post pit formed
Invagination of ventral HT & 3rd ventricle
(ectoderm)
what ant pit hormones DO NOT bind to Protein coupled receptor
Growth hormone
Prolactin
what simulates/inhibits GH
GHRH stimulates
somatostatin inhibits
what simulates/inhibits TSH
TRH stimulates
somatostatin inhibits
what simulates/inhibits PRL
dopamin inhibits
TRH and Oxytocin stimulate
what simulates/inhibits ACTH
CRH and AVP stimulate
what does TRH simulate
TSH
PRL
what does somatostatin inhibit
GH
TSH
what does dopamine inhibit
PRL
what kind of hormones are TRH, CRH, GHRH, GnRH
peptides
what kind of hormones are the following hormones:
ACTH:
LH, FSH, TSH:
GH, PRL:
ACTH: Peptide
LH, FSH, TSH: Glycoproteins
GH, PRL: Protein
in GPCR what does Gsα do
stimulates AC, makes PKA
Adenyl cyclase
Protein kinase A
in GPCR what does Gqα do
stimulates PLPC, makes PKC
Phospholipase C
Protein kinase C
what hormones bind to Gsα
CRH
ACTH
TSH
GHRH
LH,FSH
CaSR
PTH
what hormones bind to Gqα
TRH
GnRH
GHS-R
AVP (1b)
Oxy
in GPCR what does Giα do
inhibits Adenyl cyclase
what stimulates GH
Hormones:
GHRH
Ghrelin
Thyroid hormone
Estrogen
Dopamine (L-Dopa)
Glucocorticoids
Nutrition
Fasting
Hypoglycemia
- Glucagon
- Insulin
Protein/amino acids
- Arginine
Malnourished
Other:
Galanin
Alpha agonists (Clonidine)
Beta antagonists (Propranolol)
Exercise
Stress
Trauma
Sepsis
What inhibits GH secretion
Hormones:
SRIF
IGF-1
Hypothyroidism
Hyperthyroidism
Glucocorticoids
Chronic admin
Deficiency
Nutrition:
Glucose
FFA
Other:
Depression
Emotional deprivation
β-adrenergy
what hormones share a common Alpha unit and have a specific beta unit
TSH
LH
FSH
HCG
CαSβ
Common Alpha
Specific Beta
Rock the Casbah
How does TSH work at receptor
Binds GPCR (Gsα) - PKA
This increases:
- Iodide influx into cell, efflux into colloid
- Synthesis of
—NADPH
—Hydrogen Peroxide
—Thyroglobulin (TG)
—TPO
-Uptake of TG into cell, release into plasma
What stimulates TSH
TRH
Low T3
Leptin
What are TSH Inhibitors
SRIF
T3
Glucocorticoids
Dopamine (acutely)
Fasting/Starvation
Certain cytokines
Important genes for GnRH
KAL1
PROK2
FGF8
FGFR1
PROKR2
NELF
CHD7
WDR11
HS6ST1
SEMA3A
What stimulates the release of GnRH
Stimulate release:
Leptin (LEP/LEPR)
Kisspeptin (KISS1/GPR54)
PC1
Norepinephrine
Glutamate
what inhibits the release of GnRH
GABA
MKRN3
Opiate R
Estrogen
Through KISS1R
Progesterone
Decrease pulses
Testosterone
Through KISS1R
No E required
PRL is Stimulated by?
TRH
T4, T3
Estradiol
VIP
FGF, EGF
Serotonin
GHRH (GHRH tumors – higher PRL)
PRL is inhibited by?
Dopamine
Prolactin
What is PRL role
Important in pregnancy
-Mammary
- Lactation if suckling
- No milk during pregnancy
Not primary for milk ejection
Oxytocin
Inhibits LH, FSH
(Secondary amenorrhea while breast feed)
- Inhibit Kisspeptin
what stimulates vasopressin
Osmolality»_space; Volume > Pressure
1% increase in Osm = AVP release
10-fold higher required for V/P
Pain, nausea = stimulation
- Glutamate
Triple phase response to surgery/trauma
phases and lengths
DI
- Edema, “stunning”
- 12 hours – Few days
SIADH
- Necrosis, release AVP
- May last up to 2 weeks
DI
- Cell death
- Indefinite
Some don’t have the first phase and just start with SIADH
what are pathologic causes of high prolactin
Prolactinoma (> 1000ug/dl)
Stalk Compression/dissection
Hypothyroidism
Surgery
Seizure
Head Trauma
Renal Failure
Hypothalamic mass
Prolactin receptor mutation
what are physiologic causes of high prolactin
Pregnancy
Lactation
Stress
Coitus
Nipple stimulation
Sleep
Exercise
what drugs can cause high prolactin
Dopamine antagonists (Parkinson meds)
Antipsychotics: Risperidone
Estrogen
Ranitidine
Anti epileptics: Phenytoin
Opiates
Anti depression: SSRIs, TCAs
what is the cutoff for prolactinoma
> 200 ug/L
what syndrome to think of with prolactinoma
MEN1