Adrenal Gland - Fxn and Disease Flashcards
What are some signs associated with 21-beta-hydroxylase deficiency?
-low aldosterone, low cortisol, hypovolemia and hyponatremia. The system moves towards producing more sex hormone. 95% cases of adrenal corticaol hypoplasia.
what are some signs associated with 17-a-hydroxylase deficiency?
Low aldosterone but other mineralocorticoids may compensate, so those levels will rise; pts will lose most of the secondary sex characteristics. Female may lose menstruation. Stimulation of the mineralocorticoids is volume expansion, and increased BP
What is responsible for transferring cholesterol to the mitochondria and thus is deemed the rate-limiting step in the production of steroid hormones?
Steroidogenic acute regulatory protein (StAR)
ACTH is derived from post-translational processing of _.
pro-opiomelanocortin (POMC)
In response to cortisol, how are the following system affected:
- Immune system
- Liver
- Muscle
- Adipose tissue
- Suppress
- Increase glyconeogenesis and glycogenolysis
- Protein catabolism; decrease protein synthesis
- Lipolysis
When is cortisol secretion the highest and when is it the lowest?
Highest in the morning (8am) and lowest at night (12am)
What happens to a person’a ACTH levels and adrenal cells, who is on chronic exogenous adminstarion of cortisol?
ACTH levels are low cuz of negative feedback and since adrenal cortex isnt being used it may atrophy.
What is Cushing’s Syndrome
Primary hypercortisolism due to a tumor on the adrenal gland.
What is Cushing’s disease?
Secondary hypercortisolism due to a tumor on the pituitary.
What is Addison’s disease?
Primary hypocortisolism due to autoimmune disease destorying the adrenal gland
What can cause secondary adrenal insufficiency?
Chronic use of Glucocortioicd drugs suppressing hypothalamus and/or pituitary.
A pt with a moon face, presents to your clinic, complaining of excessive weight again int he abdomen, dark red or purple stretch marks, and excess fat on the back of the neck. Labortaory test shows elevated cortisol and decreased ACTH. What is the likely diagnosis?
Cushing syndrome
A patient presents with, hyperpigmentation, elevated cortisol and ACTH, and decreased CRH. what is the likely diagnosis?
Secondary hypercortisolism aka Cushings disease. Tumor on on the pituitary.
Explain how you can use Cosyntropin stimulation test to detect adrenal gland insufficiency (AI).
Cosyntropin stimulation test is a test that measure the level of hormone.
If the patient’s cortisol level is beyond 15 ug/dL then rule out AI. But if tis’ between 3-15 ug/dL then give them cosyntropin and after 30 mins measure cortisol levels. If it’s geater than 18 ug/dL then rule out AI but if it’s less then 18 then AI is confirmed. AI can also is confirmed if the initial cortisol at 8am is less thena 3 ug/dL. Once AI is confirmed then measure ACTH to find out if its primary or secondary. Primary AI will show low or normal ACTH, while primary AI will show elevated ACTH.
What cell types do aldosterone have it’s primary action on?
Principal cells of the distal nephron.
How does Aldosterone act to increase Na reabsorption?
It signals the cell to synthesize new proteins channels and pumps and also modulate existing channels and pumps.
Primarily hyperaldosteronism is also known as what disease?
Conn’s disease
What is secondary hyperaldosteronism?
Excessive renin secretion by the juxtaglomerular cells of the kidney
What catecholamines are the predominant types produced in the medulla
Epinephrine (80%). No-epi is 20%
Cortisol increases the level of what enzme which then converts Nor-epi to Epi
Phenylethoanolamine-N methyl transferase (PNMT)
Describe the pathway leading to epinephrine.
Tyrosine –> DOPA–> Dopamine –> Nor epi –> EPi
What stimulates tyrosine to be converted to DOPA?
Sympathetic stimulation via ACh acts on tyrosine hydroxylase.
What stimulates Dopamine to be converted to norepi
Sympathetic stimulation via Ach works on dopamine beta hydroxylase
How does dopamine enter the chromaffin cells?
Via VMAT1
What is the rate limiting step of Catecholamine production?
Hydroxylation of tyrosine by tryrosine hydroxylase producing DOPA
What converts DOPA to Dopamine?
cytoplasmic enzyme called aromatic amino acid decarboxylase (AADC)
True or False. Nor EPi is converted to Epi inside the chromaffin granule.
False. Nor Epi leaves the chromaffin granule and via PNMT is converted to Epi.
How does epi which is formed outside of the chromaffin granule get back into the chromaffin granule?
VMAT
Circulating chromogranins are marker for what disease?
Chromogranins are proteins that complexed with E in its storage inside the chromaffin granule. If chromoagranins are seen in circulating this indicates sympathetic paraganglion-derived tumors aka paragangliomas.
Both E and NE can be converted to dihyrxoymendelic acid via what enzyme?
monoamine oxidase (MAO)
What form of E and NE breakdown is excreted in urine and can be measured.
Vanillylmandelic acid (VMA)
alpha receptors and beta 3 receptors respond better to which catecholamine?
NE
Beta1 receptors respond better to which catecholamine?
Equally for both
which catecholamine is more potent for beta 1 receptor?
E
What symptoms are hallmark signs of pheochromocytoma
Headaches, sweating, palpitations
