adrenal hormones and testing Flashcards
(57 cards)
where is the adrenal gland located
on top of the kidney (one for each kidney)
adrenal cortex
produces and secretes steroid hormones, including cortisol aldosterone, and androgens
adrenal medulla
produces and secretes catecholamines
areas of the adrenal cortex (outside to inside)
zone glomerulosa, zona fasciculata, zone reticularis
what hormones are released from the zona glomerulosa
mineral corticoids - aldosterone
- regulate blood pressure by increasing Na2+ retention in blood excreting K+ and H+ in return
what hormones are released from the zona fascicularta
glucocorticoids - cortisol, corticosterone, cortisone
what hormones are released from the zona reticularis
androgens - dehydroepiandrosterone
what hormones are released from the adrenal medulla
epinephrine, norepinephrine
RAAS system
renin
angiotensin
aldosterone
system
true or false: there is no involvement of the hypothalamus or pituitary in the regulation of aldosterone
TRUE: however, aldosterone does stimulate the third reflex through the hypothalamus and secretion of ADH
primary aldosterone excess disorders
adrenal disorder
autonomous aldosterone production by the adrenal tumor (Conn’s disease)
too much aldosterone in the gland
secondary aldosterone excess disorders
too much aldosterone in other organs/ conditions
renin producing tumour
renal artery stenosis - impaired blood flow to the kidney
drugs - laxatives, some diuretics
increased aldosterone causes
Na+ retention: increased blood volume and hypertension hypernatremia
K+ loss: muscle weakness and cardiac arrhythmia
H+ loss: increased blood pH
investigation of aldosterone excess (high blood pressure) / deficiency
aldosterone levels
renin levels
aldosterone:renin ratio
serum or urine samples can be measured
reported in pmol/L
aldosterone excess lab testing workflow
- if the patient has excess aldosterone, measure aldosterone
- primary or secondary? measure renin and aldosterone/renin ratio
prim: decreased renin increased ratio
secondary: increased renin ratio not drastically increased
primary aldosterone deficiency
addison’s disease - destruction of adrenal cortex
enzyme deficiency in the aldosterone synthesis pathway
secondary aldosterone deficiency
renin deficiency
aldosterone deficiency causes
Na2+ loss: water loss, dehydration, decreases blood pressure, weakness
K+ retention: muscle weakness and cardiac arrhythmia
H+ retention: decreased blood pH (blood is more acidic)
aldosterone deficiency lab workflow
- does the patient have decreased aldosterone? measure aldosterone
- is the case primary or secondary? measure renin and aldosterone/renin ratio
primary: increased renin decreased ratio
secondary: decreased renin not drastically decreased ratio
renin activity testing
- not well standardized
- fairly manual and time-consuming
- can incubate for prolonged period of time to generate a signal in low renin samples
- technical process dependant on many variables
- have been used longer
renin mass
- calibrated against an international reference standard
- can be automated
-may not be able to measure renin concentrations as low as renin activity assays
-better intra and inter-assay reproducibility - in use for a shorter period
true or false: cortisol increases during times of stress
true
the effect of cortisol on carbohydrate, protein, and lipid metabolism
increases blood glucose through gluconeogenesis
increases protein breakdown
increased lipolysis
cortisol is an insulin antagonist
… facilitates catecholamine effects by increases blood pressure
cortisol
