Adrenal Gland Flashcards
CRH is stimulated by…
Decreased plasma cortisol, hypoglycemia pyrogen and stress
CRH comes from…
Hypothalamus
CRH is suppressed by…
Increased plasma glucocorticoid level
ACTH comes from…
Anterior pituitary
AVP has a ___ on the anterior pituitary
Stimulatory
Cortisol has an ___ on the hypothalamus and anterior pituitary
Inhibitory
Zona glomerulosa secretes…
Aldosterone
Zona fasciculata secretes…
Cortisol and corticosterone
Zona reticularis secretes…
Sex steroids
The adrenal medullar secretes…
Catecholamines (epi & norepinephrine)
What is the first step common to the formation of all steroids
The formations of pregnenolone to cholesterol
Where does steroidogenesis take place
Mitochondria
The uptake of cholesterol is….
A rate limiting step
What is StAR and what does it do
It is a cAMP inducible gene and it increases in response to tropic hormones
What is responsible for the conversion of pregnenolone from cholesterol in the mitochondria
P450scc
Steroidgeneic enzymes depend on…
Electron transfer proteins
Mitochondrial electron transporters
ADR and ADx
Microsomal electron transporters
POR or B5
What is the main source of cholesterol to make steroid hormones
Circulating LDL
What determines steroid production
Zone specific expression of enzymes
How do most steroid differ
Hydroxyl groups (minor modifications)
What effect does cortisol have on metabolism
Increased: gluconeogenesis, glycogenolysis, proteolysis, lipolysis
What effect does cortisol have on the cardiovasculuar system
Increased: myocardial contractility, cardiac output and catecholamine pressor effect
What transports circulating cortisol
Corticosteroid binding globulin
What happens to cortisol since it isn’t stored
Converted to inactive cortisone and other metabolites by the liver
What is the function of CBG
Protects cortisol from inactivation by the liver
Glucocorticoid receptor beta inhibits…
Glucocorticoid receptor alpha
Cortisol has an __ in the liver
Anabolic
What is Cushing’s syndrome
An overproduction of cortisol
What is Addison disease
Adrenal hypofunction
What is the main function of aldosterone
Recovery of Na in the kidney and enhance K secretion into the urine to balance charge difference (also water retention and dilation of arterioles)
The diameter of ___ is a major determinant of the blood pressure in arteries
Arterioles
What increases sodium appetite
Aldosterone, angiotensin II, decreased sodium in brain
What decreases sodium appetite
Circulating & CNS peptide hormones, post-ingestive signals from gut, increased in NA blood plasma
Where is angiotensin converted to angiotension I
Afferent arterioles in kidneys by renin
Where is angiotension I converted to angiotension II
Endothelial cells of the lungs by ACE
Angiotensin II stimulates…
Aldosterone secretion
Where does aldosterone mainly act
Distal tubules and collecting ducts of kidney
What is the net effect of aldosterone
Rise in plasma volume and blood pressure
Conn’s disease
Hypersecretion of aldosterone, increased water retention
Natriuretic peptides
Peptides that increase the excretion of water and Na
Where are natriuretic peptides produced and stored
Heart muscle; granules
What is the function of natriuretic peptides
Increases glomerular filtration and reduces blood volume and pressure
Adrenal cortex contributes to the production of…
DHEAS and androstenedione
Most common form of congenital adrenal hyperplasia involves deficiency of…
CYP21A2
Congenital adrenal hyperplasia results in reduced ___ and increased ___
Cortisol and aldosterone; androgen production
What is the rate limiting step in the synthesis of catecholamines from tyrosine
Tyrosine hydroxylase
What stimulates the conversion of norepinephrine to epinephrine
Phenylethanolamine N-methyltransferase (PNMT), stimulated by cortsiol
What inactivates epinephrine and norepinephrine and to what
MAO and COMT, to VMA, which is excreted in the urine
What are enkephalins
Other hormones secreted by adrenal medulla, block neurotransmitters, like morphine
What receptors bind epinephrine and norepinephrine
Alpha and beta1,2 adrenegic receptors
If cortisol levels are suppressed…
It results in epinephrine deficiency
