Adrenal Glands II - Cortisol, Androgens, Catecholamines Flashcards
describe ACTH signaling pathway
cAMP at the adrenal gland
describe cortisol signaling pathway
binds intracellular receptor and modulates gene expression (since it’s a steroid)
describe functions of cortisol
- physiologically it mediates adaptive responses to stress and fasting
- mobilizes all the fuel resources
- pharmacologically it supresses inflammatory and immune responses
describe the effect of cortisol at target organs
- liver: increase glucose and glycogen production. increases plasma protein production
- fasting state = increase in glucose
- non-fasting state = excess glucose -> back to glycogen
- muscle: increase protein breakdown in muscles to generate amino acids that will be shunted to liver for gluconeogenesis
- adipose cells: increases lipolysis to create free fatty acids which will inhibit insulin, glycerol to liver for gluconeogenesis
describe the effects of cortisol on CNS
- crosses BBB and acts on limbic structures
- has major impact on mood
- normal levels required for normal mood
anti-inflammatory effect: cortisol direcly inhibits ____ synthesis by supressing ____
immunosuppresive effect: exerts an anti-inflammatory response via ______ which inhibits _______ to site of inflammation
suppresses ____ & _____ and _______
- directly inhibits PG synthesis by supressing COX 2
- exerts an anti-inflammatory response via lipocortin-1 which inhibits neutrophil, eosinophils and monocytes migration to site of inflammation
- supresses T and B lymphocytes and IL-2
- prevents proliferation and collagen synthesis by fibroblasts (poor wound healing)
describe the transport of cortisol
__% is bound and ___% is unbound
what causes an increase in CBG levels?
- bound to corticosteroid binding globulin (CBG or transcortin)
- 96% is bound and 4% is unbound
- increase in CBG levels caused by:
- pregnancy due to increased levels of estrogen
- hyperthyroidism
- birth control pills
there is no _____ with androgens
there is no negative feedback with androgens
only way to shut system off is with negative feedback by cortisol. If cortisol is not produced in females, increase in androgen production and masculinization
- primary adrenal insufficiency is due to destruction of ____
- secondary adrenal insufficiency causes decrease production of ____
- secondary adrenal insufficiency causes decrease production of ____
- primary = destruction of adrenal gland
- results in cortisol and aldosterone deficiency
- secondary = decrease in ACTH production
- cortisol deficiency (aldosterone preserved)
- tertiary = decrease in CRH production
- cortisol deficiency (aldosterone preserved)
describe Addison’s disease
- due to autoimmune destruction of all zones of the adrenal cortex
- results in loss of all hormones
- there is increased secretion of ACTH leading to hyper-pigmentation of skin because of increased alpha-MSH molecules
contrast Cushing’s syndrome vs Cushing’s disease
- Cushing syndrome is due to chronically elevated levels of glucocorticoids
- due to adrenal tumor
- exogenous glucocorticoids
- Cushing’s disease is due to excess secretion of ACTH from pituitary tumor resulting in excess glucocorticoids
describe 21-hydroxylase deficiency
- no enzyme to convert progesterone and OH-progesterone into aldosterone and cortisol
- hypotension and hyperkalemia
- hypoglycemia
-
only adrogens can be produced since no negative feedback from cortisol
- massive amounts of androgens produced
describe 17 alpha hydroxylase deficiency
- decrease in cortisol production, increased ACTH production
- increased deoxycorticosterone and aldosterone production
- increase in BP, ECF, Na and H2O
- decrease in renin and AG II
the adrenal medulla secretes ___% epi and ___% nor
80% epi, 20% norepi
explain cell signaling in chromaffin cells
- Ach binds to nicotinic receptor
- increases Ca levels, exocytosis of epi and nor
describe the stress pathway
