hormones Flashcards
What does oxytocin do?
Works on the breast to eject milk
positive feedback with contraction strength
what cell in the breast tissue does oxytocin act on?
myoepithelial cells
What area in the breast tissue does PRL work on?
alveolar
What area is MSH produced in AP?
Pars Nervosa
What nucleus releases ADH?
Supraoptic
What nucleus releases oxytocin?
paraventricular
What antibody do you test for with graves dz
TSI
TSHR
What antibody test do you run for hashimotos?
Anti TPO
What is the release pattern of GH?
pulsatile; peaks during sleep
What are release triggers for GH?
stress exercise DEC glucose/FA high protein meal fasting ghrelin levodopa apomorphine bromocriptine
What pathway does GH work through when it binds to its receptor?
JAK/STAT (nontyrosine kinase)
What are the actions of GH?
decreases adiposity
decreases glucose use (inc BG)
What are the actions of IGF1?
inc lean muscle mass
inc linear growth
inc organ growth
What can inc GH cause?
children: gigantism
adults: acromegaly
What are the characteristics of congenital short stature?
normal GH
lack of IGF1 during puberty
What pathway/receptor does GHRH work through?
G protein
cAMP and inc Ca
Is there anything that inhibits GH release?
YES! somatostatin
What is the release pattern for PRL
pulsatile
What pathway does PRL work through?
JAK/STAT (non tyrosine kinase receptor)
What does PRL do?
breast development
milk production
inhibition of gonadotropins
What stimulates PRL release?
suckling, stimulation, stress, sleep, neurogenic reflex, phenothiazines, INC estrogen, pregnancy
what inhibits PRL? non hormonal inhibition?
dopamine, bromocriptine, apomorphine
What can excess PRL cause?
galactorrhea, infertility, amenorrhea, decreased libido, dec spermatogenesis
What two things are associated with inc PRL?
prolactinomas, empty sella syndrome
What receptor does TRH work through?
g prot to IP3 to inc Ca
What receptor does TSH work through?
g prot to cAMP
What are the actions of thyroid hormones?
bone and CNS maturation
inc BMR ( inc heat production)
Inc CO
inc metabolism
What are the symptoms of hyperthyroidism?
wt loss sweating inc CO tremor/muscle weakness exopthalmos
What are the symptoms of hypothyroidism
wt gain cold sensitivity lethargy, mental slowness drooping eyelids myxedema growth retardation mental retardation
What is the treatment for graves?
PTU
What is the effect of hyperthyroidism on T4, TSH, and binding proteins?
T4-high
TSH-low
proteins- normal
What is the effect of hypothyroidism on T4, TSH, and binding proteins?
T4-low
TSH-high
proteins-normal
What will happen with a cholesterol desmolase deficiency?
rate limiting step from cholesterol to pregnenolone
fatal
What will happen with a 3 beta hydroxy steroid dehydrogenase deficiency?
no cortisol no aldo no androgens DHEA build up fatal
what will happen with a 17 alpha hydroxylase deficiency?
very low cortisol and androgens
inc aldo
both sexes have female phenotype
hypokalemia
What will happen with a 21 beta hydroxylase deficiency?
very low cortisol and aldo (na loss and hypotension)
DHEA and androgen build up (virilization, hirsutism, amenorrhea)
females born with ambiguous genitalia and raised as male
associated with congenital adrenal hyperplasia
What will happen with a 11 beta hydroxylase deficiency?
inc deoxycorticosterone (na ret and htn) inc DHEA and androgens (virilization) very low aldo and cortisol (as its the final enzyme needed to create them)
What enzyme deficiency is most common?
21 beta hydroxylase
What stim aldo?
ang II
what downregulates aldo?
ANP
what are the effects of cortisol?
inhibits protein synth promotes FA use dec glucose use stim gluconeogenesis antiinflammatory
What receptor does CRH work through?
g prot to cAMP to ca
what receptor does ACTH work through
g prot to cAMP
what is the release pattern of cortisol?
circadian rhythm
what are stimulators of cortisol?
stress, DEC glucose
what happens when you lose cortisol?
circulatory failure
inability to readily mobilize energy sources
inhibits t cell production
what is the most common cause of congenital adrenal hyperplasia
21 beta hydroxylase
what is released from the adrenal medulla?
epi and norepi
what is released from the zona glomerulosa
aldo
what is released from the zona fasciculata
cortisol
what is released from the zona reticulata
androgens
what are the signs of cushings?
moon face, striae, truncal obesity, HTN, osteoporosis, protein depletion, mental abnormalities, DM hirsutism
hypokalemia and alkalosis
what is the most common cause of cushings?
prednisone use
what is the best way to test for cushings?
24 hr cortisol
What are the steps for suspected hyperadrenalism?
1- low dose dexamethasone suppression test (if normal, not cushings)
2- 24 hr urine cortisol (if normal, not cushings)
3- high dose of dexamethasone suppression test
What do the results of the high dose dexamethasone test signify:
1) >50% decrease in cortisol
2) no response
3) ACTH level high
4) ACTH level reduced
1) cushings due to pituitary adenoma
2) ACTH secreting tumor
3) ACTH secreting tumor from another source ie lung
4) adrenal tumor
What is conn’s syndrome? how is it diagnosed
inc levels of aldo
primary hyperaldosteronism
inc ratio PAC/PRA = 25-50
how do you test for primary aldosteronism?
saline suppression test
measure PAC
if falls below 5- normal
if remains above 10- primary
How do you test for pheochromocytoma?
24 metanephrine and catecholamine urine collection
how do you confirm pheo presence?
give clonidine to suppress
MRI or CT
What test should you always run with a suspected pheo?
MIBG to see if theres any extra adrenal tumors
What are the actions of PTH in the kidney?
inc Ca reabsorption
inc PO4 excretion
inc act of vit D
What are the actions of PTH in the GI tract?
inc vit D -> inc Ca absorption
what are the action of PTH on the bone?
inc bone resorption
through osteoblast cytokines to osteoclasts
RANKL binding RANK
What is measured to see if bone is being broken down?
alkaline phosphatase
what is the job of calcitonin?
antagonizes PTH
dec bone resorption
dec kidney reabsorption of Ca
how does PTH respond in acidosis?
inc ionized Ca
so no PTH release
how does PTH respond in alkalosis?
dec ionized Ca
inc PTH release
what cells secrete PTH?
chief cells
Other than calcium, what stimulates PTH?
dec Mg
inc PO4
what does dec PO4 do?
inc vit d activation
what does inc PTHrP signify?
malignancy
What pathway does Ca inhibition of PTH work through?
G prot with IP3 releases Ca and inhibits PTH release
stim by Ca
what pathway does PTH work through on the kidney?
g prot to camp to protein kinase to phos of phosphate/Na symporter dec the phos reabsorption
what is the treatment for hypoparathyroidism
Vit D
Ca supplement
what do the labs look like for primary hyperparathyroidism (PTH, Ca, P, Vit D)
inc PTH
inc Ca
dec P
inc Vit D
what do the labs look like for secondary hyperparathyroidism (PTH, Ca, P, Vit D)
inc PTH
dec Ca
dec P
dec Vit D
what do the labs look like for primary hypoparathyroidism (PTH, Ca, P, Vit D)
dec PTH
dec Ca
inc P
what do the labs look like for secondary hypoparathyroidism (PTH, Ca, PO4, Vit D)
dec PTH
inc Ca
inc P
Inc Vit D possibly
what do the labs look like for pseudo hypoparathyroidism (PTH, Ca, P, Vit D)
*resistance to PTH
inc PTH
dec Ca
inc P
what do the labs look like for postmeno/immobilization hypoparathyroidism (PTH, Ca, P, Vit D)
dec PTH
inc Ca
inc P
*bone being broken down
what do the labs look like for inc PTHrP hypoparathyroidism (PTH, Ca, P, Vit D)
dec PTH inc Vit D inc Ca inc urine phosphate dec P *acts like PTH
what do the labs look like for renal failure (PTH, Ca, P, Vit D)
inc PTH
dec Vit D
dec Ca, due to dec in Vit D
dec P
What is familial hypocalciuria hypercalcemia?
mutated Ca receptor -> inc Ca levels
takes mores Ca to turn off PTH than normal
what stim act of Vit D
inc PTH
dec Ca
dec P
what 3 things stimulate insulin secretion?
inc blood glucose
inc CCK, GIP
inc parasympathetic activity
what is insulins action on hepatocytes/
inc hexokinase which leads to inc glycogen
how does dec insulin lead to polyphagia?
insulin usually feeds back to the hypothalamus to tell you that you are full
when there is none, the body thinks theres low glucose and tells you to eat
how does dec insulin lead to polyuria and polydipsia
inc blood glucose leads to diuresis and inc plasma osmolarity both lead to thirst center activation
how does dec insulin lead to kussmaul breathing
leads to inc ketones -> metabolic acidosis -> inc RR
