Immunopharm - Glucocorticoids/Asthma/COPD Flashcards
Overview of the adrenal cortex:
- Outer cortex is derived from ____ and the inner medulla is derived from?
- What are the three zones? What is produced in each?
Overview of the adrenal cortex:
- Outer cortex: mesoderm
- Inner medulla: neural crest cells
- Zona glomerulosa - mineralocorticoids
- Zona fasciculata - glucocorticoids
- Zona reticularis - androgens
Overview of the adrenal cortex:
- Function of mineralocorticoids?
- Function of glucocorticoids?
Overview of the adrenal cortex:
- Mineralocorticoids: H2O/electrolyte balance, active reabsorption of Na+ by kidneys, passive water reabsorption, and active secretion of K+ and H+
- Glucocorticoids: glucose metabolism and anti-inflammatory proterties
Overview of the adrenal cortex:
Glucocorticoid synthesis is regulated by _____ which is released from ___ cells in the ___ ____. Its synthesis is regulated by ____. A negative feedback inhibition occurs in that high ___ levels decrease the synthesis and release of ___ and ___ and thus the absence of ___ leads to atrophy of the zona ____ and zona reticularis.
Overview of the adrenal cortex:
Glucocorticoid synthesis is regulated by ACTH which is released from corticotroph cells in the anterior pituitary. Its synthesis is regulated by CRH. A negative feedback inhibition occurs in that high cortisol levels decrease the synthesis and release of CRH and ACTH and thus the absence of ACTH leads to atrophy of the zona fasciculata and zona reticularis
Synthesis of steroid hormones:
- What is the rate limiting step?
- What enzymes are needed to get from progesterone to aldosterone?
Synthesis of steroid hormones:
- Rate limiting step is the conversion of cholesterol to pregnenolone
- Progesterone –> 21 hydroxylase –> 11-hydroxylase –> aldosterone synthase –> aldosterone
Synthesis of steroid hormones:
- What enzymes are neeed to convert pregnenolone to cortosol?
- What are the steps from pregnenolone to testosterone?
Synthesis of steroid hormones:
- Pregnenolone –> 17 hydroxylase –> 21 hydroxylase –> 11 hydroxylase –> cortisol
- Pregnenolone –> DHEA –> androstenedione –> T
Drugs inhibiting steroid synthesis:
Why are these more systemically toxic?
Name 4 drugs.
Drugs inhibiting steroid synthesis:
More systemically toxic bc they inhibit CYP450
Mitotane, aminoglutethimide, ketoconazole, and metyrapone
Drugs inhibiting steroid synthesis:
Mitotane:
- Toxic to ____ cells and used as an ____ agent in adrenal tumors.
- MOA?
Drugs inhibiting steroid synthesis:
Mitotane:
- Toxic to adrenocortical cells and used as an antineoplastic agent in adrenal tumors
- MOA: unknown
Drugs inhibiting steroid synthesis:
Aminoglutethimide:
- Used to treat?
- MOA?
- Dose dependent __ and ___ side effects and rash, causes ___ insufficiency.
Drugs inhibiting steroid synthesis:
Aminoglutethimide:
- Use: breast cancer in postmenopausal women and metastatic prostate cancer
- MOA: blocks cholesterol side chain cleavage enzyme
- Dose dependent GI and neurological side effects and rash, causes adrenal insufficiency
Drugs inhibiting steroid synthesis:
Ketoconazole:
- ____ agent for?
- Second line treatment for?
- MOA?
- Major side effect?
Drugs inhibiting steroid synthesis:
Ketoconazole:
- Antifungal agent for athletes foot, ringworm, and dandruff
- Second line for cushings
- Inhibits 17 hydroxylase and 14 demethylase
- SE: hepatotoxicity
Drugs inhibiting steroid synthesis:
Metyrapone:
- Used to treat?
- MOA?
Drugs inhibiting steroid synthesis:
Metyrapone:
- Hypercorticism from neoplasm
- Selective inhibitor of 11-hydroxylase
Glucocorticoids:
Cortisol:
Major ___ steroid. __ at the 11th position.
Function?
Glucocorticoids:
Cortisol:
Major endogenous steroid. Hydroxyl at the 11th position.
Functions: suppress immune system, increase gluconeogenesis, fat/protein/carbohydrate metabolism
Glucocorticoids:
Corticosterone:
Why is this inactive? What activates it?
Glucocorticoids:
Corticosterone:
Inactive because there is a carbonyl at the 11th carbon (instead of carboxyl) - becomes metabolized by 11 hydroxysteroid dehydrogenase to a hydroxyl at the 11th carbon
Glucocorticoids:
Prednisone is a prodrug converted to?
Fludrocortisone: level of glucocorticoid activity?
Glucocorticoids:
Prednisone is converted to prednisolone
Fludrocortisone: higher mineralocorticoid potency, higher glucocorticoid activity than cortisol but not overly high in comparison to others
Glucocorticoids:
Prednisolone/Methylprednisolone: ____ times more potent than cortisol for ______ activity. Low ____ activity.
Dexamethasone: Greater than ___ times more potent than cortisol with ___ mineralocorticoid activity.
Glucocorticoids:
Prednisolone/Methylprednisolone: 4-6 times more potent than cortisol for anti-inflammatory activity. Low mineralocorticoid activity
Dexamethasone: Greater than 18 times more potent than cortisol with no mineralocorticoid activity
Inhaled glucocorticoids:
Why are they better?
Name 4.
Inhaled glucocorticoids:
Deliver high concentrations to the lung with less systemic toxicity
Fluticasone, Beclomethasone, Flunisolide, and Triamcinolone
Glucocorticoids:
MOA: 90% is bound to ___ with the receptor for the ____ complex on the ____. ____ transport into the cell. Binds to ___ glucocorticoid receptor and _____. This ____ complex is transported to the ___ and regulates (either up or down) transcriptional expression of genes.
Glucocorticoids:
MOA: 90% is bound to CBG (corticosteroid binding globulin) with the receptor for the CBG-S complex on the surface. Active transport into the cell. Binds to T2 glucocorticoid receptor and dimerizes. This GR-S complex is transported to the nucleus and regulates (either up or down) transcriptional expression of genes
Glucocorticoids:
Metabolic effects:
- Antagonizes ___ action and promotes ____ (increases blood ____)
- What does it do to muscle?
- Augments growth hormone action on ____ (increased blood _____)
Glucocorticoids:
Metabolic effects:
- Antagonizes insulin action and promotes gluconeogenesis (increases blood glucose)
- Increases muscle catabolism
- Lipolysis (increased blood triglycerides)
Glucocorticoids:
Antiinflammatory actions of glucocorticoids? (3)
Glucocorticoids:
a. Decrease inflammatory response
b. Reduces cytokine release
c. Reduces production of eicosanoids
Glucocorticoids:
- Absorption?
- Binding of cortisol?
- Difference between binding of synthetics?
- Metabolism?
Glucocorticoids:
- Well absorbed in GI
- Cortisol is highly bound to cortisol binding globulin (CBG) and albumin
- Synthetics are much less bound
- Liver
Glucocorticoids:
Is the uce of prednisone during pregnancy safe? Why or why not?
Glucocorticoids:
Yes. There is no 11b-hydroxysteroid dehydrogenase I in the fetal liver
Glucocorticoids:
Therapeutic uses? (6)
Glucocorticoids:
Therapeutic uses:
a. Replacement therapy - for adrenal insufficiency
b. Anti-inflammatory
c. Inhaled for asthma
d. Topical for psoriasis and dermatitis
e. Depot injections for arthritis or gout
f. immunosupression - trasplant rejection
Glucocorticoids:
- Why are they inhaled?
- What is topical dosing for?
- What are depot injections for?
- All are for ___ ONLY!
Glucocorticoids:
- Inhaled for asthma
- Topical dosing for psoriasis and dermatitis
- Depot injections for gout and arthritis
- *** TEMPORARY RELIEF ONLY!! NO change in underlying disease
Glucocorticoids:
Toxic side effects:
- Increased susceptibility to ___
- Increased ___ levels ( ____)
- Secondary ______ . This can lead to _____.
- Increased vascular permeability leading to ____.
Glucocorticoids:
Toxic side effects
- Increased suceptibility to infection
- Increased glucose levels (diabetes)
- Secondary hyperparathyroidism. This can lead to osteoporosis
- Edema
Glucocorticoids:
Toxic side effects:
- Suppression of ___ ___ growth in children
- Steroid ____
- ____ syndrome
- Withdrawl “rebound - ____ ____
- Muscular weakness - ____
Glucocorticoids:
Toxic side effects:
- Suppression of _linear bone _ growth in children
- Steroid psychosis
- CUSHINGS** **syndrome
- Withdrawl rebound - adrenal insufficiency
- myopathy
Primary adrenal insufficiency:
___ disease: self destruction of the ___ ___ by __ cell mediated autoimmune reaction. Insufficient ___ production. Requires lifelong treatment.
Symptoms?
Primary adrenal insufficiency:
Addisons disease: self destruction of the adrenal cortex by T cell mediated autoimmune reaction. Insufficient steroid production. Requires lifelong treatment.
SE: weakness, fatigue, hypotension, hypoglycemia, salt craving, dehydration, joint/muscle pain, and hyperpigmentation
Secondary adrenal insufficiency:
Decrease in ___ causes a decrease in cortisol and ____ production. This is due to an impairment of the ____ or ____. Can also be caused by sudden ___ of long term glucocorticoid therapy.
SE?
Secondary adrenal insufficiency:
Decrease in ACTH causes a decrease in cortisol and androgen production. This is due to an impairment of the pituitary or hypothalamus. Can also be caused by sudden withdrawl of long term therapy.
SE: weakness, fatigue, hypotension, hypoglycemia, salt craving, dehydration, and joint/muscle pain