Exam 3 Lesson 19 Flashcards
Pathway from cholesterol to aldosterone/mineralocorticoids
Cholesterol – pregnenolone – progesterone – deoxycorticosterone – corticosterone – 18-hydroxycorticosterone – aldosterone – mineralocorticoids
pathway from cholesterol to cortisol/glucocorticoids
Cholesterol – pregnenolone – 17-hydroxypregnenolone – 17-hydroxyprogesterone – 11-deoxycortisol – cortisol/glucorticoids
pathway from cholesterol to androstenedione/androgens
Cholesterol – pregnenolone - 17-hydroxypregnenolone – Dehydroepiandrosterone – androstenedione / androgens
pathway from progesterone to cortisol/glucorticoids
Progesterone – 17-hydroxyprogesterone – 11-deoxycortisol – cortisol/glucocorticoids
pathway from progesterone to androstenedione/androgens
progesterone – 17-hydroxyprogesterone – androstenedione/androgerns
what does zona glomerulosa secrete? What regulates its secretion?
aldosterone (mineralocorticoid)/ renin-angiotensin
what does zona fasciculata secrete? What regulates its secretion?
cortisol (glucocorticoid)/ACTH
what does zona reticularis secrete? What regulates its secretion?
dehydroepiandrosterone/ACTH
what is congenital adrenal hyperplasia (CAH)?
genetic enzymatic defects in cortisol synthesis. The adrenal cortex will still respond to ACTH, so hyperplasia will develop
what is a cause of CAH?
inborn defect to 21-hydroxylase. Its precursor is converted to androgen instead. Aldosterone lacking causes hypoaldosteronism. You will see hypotension and low Na+ in plasma)
what are cortisol and corticosterone?
glucocorticoids
what are aldosterone and deoxycorticosterone?
mineralocorticoids
what are DHEA, DHEA-S, androstenedione?
androgens
what does cortisol regulate?
intermediary metabolism
how are cortisol effects permissive?
cortisol doesn’t directly initiate metabolic or circulatory processes, but it is necessary to permit their full expression
how does ACTH regulate cortisol?
ACTH has a GCPR that is coupled with Gs, which activates adenylyl cyclase, cAMP, and in turn, PKA, which turns on the cholesteryl ester hydroxylase in the lipid proteins that turn cholesteryl esters into free cholesterol. Then the free cholesterol can go on to become cortisol.
where does ACTH come from?
anterior pituitary
What happens to cortisol once it is secreted?
it can become free cortisol in the plasma. Then, it will either bind to a cotisol-binding protein or it will be absorbed by tissue.
which proteins bind with cortisol in the plasma?
Corticosteroid-binding globulin or albumin
how large is corticosteroid-binding globulin? Where is it synthesized and secreted?
50 KD, in the liver
11Beta-hydroxysteroid dehydrogenase
enzyme used to convert cortisol to cortisone and vice versa
11beta-HSD 2
converts cortisol to cortisone
11beta-HSD 1
converts cortisone to cortisol
which is inactive? Cortisol or cortisone? Active?
cortisol is active/ cortisone is inactive.
why can’t cortisone bind to mineralocorticoid or glucocorticoid receptors?
because it is inactive. Cortisol can because it is active.
what is the half life of cortisol?
70-90 minutes
how does cortisol regulate carbohydrate metabolism?
increases glucose supply/decreases body’s glucose utilization
how does cortisol regulate protein metabolism?
decreases amino acid utilization, except in liver
how does cortisol regulate fat metabolism?
increases fatty acid/glycerol mobilization; stimulates appetite and fat deposition in trunk area
How does cortisol maintain normal vascular integrity?
it preserves volume of body fluids, and its absence can cause vasodilation and bp to fall
what do glucocorticoids suppress?
inflammation and immune reactions
how does cortisol affect the CNS?
it provides negative feedback control; modulates perceptions and emotion.
what is cortisol important for in development?
development and maturation of tissues like intestinal enzymes and lung surfactants
what happens if glucocorticoid levels are high after birth?
they inhibit skeletal growth
Hypothalamic-pituitary-adrenal axis: what does hypothalamus release to pituitary?
CRH and vasopressin
Hypothalamic-pituitary-adrenal axis: what does pituitary release after being stimulated?
ACTH
Hypothalamic-pituitary-adrenal axis: what does adrenal gland release?
steroid hormones
Hypothalamic-pituitary-adrenal axis: how does cortisol affect the axis?
it provides feedback inhibition
addison disease
primary hypoadrenalism by adrenal cortex destruction (infection or autoimmune disease). Symptoms include low cortisol and aldosterone levels and high ACTH levels
cushing syndrome
high ACTH. Stimulates glucocorticoid oversecretion
conn syndrome
mineralocorticoid excess (tumor growth). Symptoms are hypertension and hypokalemia (low potassium)
excess glucocorticoid effect: brain/CNS
depression/psychosis
excess glucocorticoid effect: endocrine system
decrease LH, FSH, TSH release, GH secretion
excess glucocorticoid effect: liver/ carb and lipid metabolism
increase in hepatic glycogen deposition; increase in peripheral insulin resistance; increase in gluconeogenesis; increase in free fatty acid production; overall diabetogenic effect
excess glucocorticoid effect: cardiovascular/renal
salt and water retention; hypertension
excess glucocorticoid effect: adipose tissue distribution
promotes visceral obesity
excess glucocorticoid effect: bone and calcium metabolism
decrease in bone formation, decrease bone mass and osteoporosis
excess glucocorticoid effect: growth and development
decrease in linear growth
excess glucocorticoid effect: skin/muscle/connective tissue
protein catabolism/ collagen breakdown; skin thinning; muscular atrophy
excess glucocorticoid effect: immune system
Anti-inflammatory action; immunosuppresion
