L13 Cortocosteroids Flashcards
Corticosteroids are a member of what type of hormones
Steroid
Corticosteroids are secreted by what
the cortex of the adrenal gland
Where are the adrenal glands located?
Above the kidney
What are the major regions of the adrenal gland
Capsule
Adrenal cortex
Adrenal Medulla
There are two major types of corticosteroids
Mineralocorticoids and glucocorticoids
Like aldosterone and cortisol
What are mineralocorticoids’ functions
- regulate water and electrolyte balance
- Principal endogenous mineralocorticoids
What are glucocorticoid functions
- Regulate carbohydrate and protein metabolism
- are principal endogenous glucocorticoids
What effect do mineralocorticoids have with glucocorticoids
Some glucocorticoids, such as cortisol and several synthetic derivatives (drugs), also exert some mineralocorticoid activity due to incomplete receptor selectivity
Why are glucocorticoids important?
- endogenous cortisol promotes metabolic changes that
allow us to adapt to physiological stresses - Synthetic glucocorticoids suppress inflammation, allergy
& immune responses
What controls the production of cortisol from glucocorticoids
The HPA (hypothalamic pituitary adrenal) axis
Corticotrophin-releasing hormone from what stimulates release of what and from where
(CRH) from the hypothalamus stimulates the release of corticotrophin (ACTH) from the anterior pituitary gland
Corticotrophin stimulates _____ production by the adrenal cortex
Cortisol
Cortisol exerts physiological effects on many tissues and also inhibits ____ and CRH via a negative feedback loop
corticotrophin
Synthesis of endogenous cortisol
- glucocorticoids are not stored preformed, but synthesized and released as needed.
- cholesterol, is converted to pregnenolone, in a rate-limiting step regulated by corticotrophin
- Pregnenolone is converted by a series of enzymatic steps to cortisol
Diagram of cortisol production from cholesterol
Cholesterol
↓
Pregnenolone
↓
Cortisol (has ketone and OH groups)
Ketoconazole
an anti-fungal drug, blocks cortisol synthesis by inhibiting cholesterol side-chain convertase
What does stress do to cortisol
Increase cortisol levels
Diagram of the actions of cortisol
Stress
↓
HPA
↓
Cortisol
↓
bind to cortisol-binding globulin in blood and go to tissues
↓
Will bind to cytosolic glucocorticoid receptor
↓
Translocate to cell nucleus
↓
Transcription of glucocorticoid-responsive genes
↓
Protein translation
↓
Effects metabolism