adrenal hoemones Flashcards
what are glucocorticoids?
• Endogenous glucocorticoids (ex. cortisol) are responsible for
normal metabolism & resistance to stress.
• Their receptors are intracellular.
• Patients with GC deficiency have hypoglycemia &
hypotension during stress.
what are mineralocorticoids
increase reabsorption of sodium & water
& cause potassium loss.
what are the glucocorticoids actions
Promote normal intermediary metabolism:
Glucocorticoids favor gluconeogenesis through increasing
amino acid uptake by the liver and kidney and elevating
activities of gluconeogenic enzymes.
They stimulate protein catabolism and lipolysis, thereby
providing the building blocks and energy that are needed for
glucose synthesis
Increase resistance to stress:
By raising plasma glucose levels,
glucocorticoids provide the body with the energy
it requires to combat stress caused by trauma,
fright, infection, bleeding, or debilitating
disease.
Alter blood cell levels in plasma:
Glucocorticoids cause a decrease in eosinophils,
basophils, monocytes, and lymphocytes by
redistributing them from the circulation to
lymphoid tissue.
They increase the blood levels of hemoglobin,
erythrocytes, platelets, and neutrophils.
Have anti-inflammatory action:
The most important property is their ability to reduce the
inflammatory response and to suppress immunity.
The lowering and inhibition of peripheral lymphocytes and
macrophages is known to play a role.
Also the indirect inhibition of phospholipase A2
, which blocks the
release of arachidonic acid.
Inhibit the synthesis of COX-2.
Inhibit the production of prostaglandins & leukotrienes.
In addition, interference with mast cell degranulation results in
decreased histamine release and capillary permeability
Affect other components of the endocrine
system:
Feedback inhibition of corticotropin production
by elevated glucocorticoids causes inhibition of
further synthesis of glucocorticoid and TSH
what are the glucocorticoids actions
Promote normal intermediary metabolism:
Glucocorticoids favor gluconeogenesis through increasing
amino acid uptake by the liver and kidney and elevating
activities of gluconeogenic enzymes.
They stimulate protein catabolism and lipolysis, thereby
providing the building blocks and energy that are needed for
glucose synthesis
Increase resistance to stress:
By raising plasma glucose levels,
glucocorticoids provide the body with the energy
it requires to combat stress caused by trauma,
fright, infection, bleeding, or debilitating
disease.
Alter blood cell levels in plasma:
Glucocorticoids cause a decrease in eosinophils,
basophils, monocytes, and lymphocytes by
redistributing them from the circulation to
lymphoid tissue.
They increase the blood levels of hemoglobin,
erythrocytes, platelets, and neutrophils.
Have anti-inflammatory action:
The most important property is their ability to reduce the
inflammatory response and to suppress immunity.
The lowering and inhibition of peripheral lymphocytes and
macrophages is known to play a role.
Also the indirect inhibition of phospholipase A2
, which blocks the
release of arachidonic acid.
Inhibit the synthesis of COX-2.
Inhibit the production of prostaglandins & leukotrienes.
In addition, interference with mast cell degranulation results in
decreased histamine release and capillary permeability
Affect other components of the endocrine
system:
Feedback inhibition of corticotropin production
by elevated glucocorticoids causes inhibition of
further synthesis of glucocorticoid and TSH
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what are the mineralocorticoids actions (Aldosterone)
Help to control the body’s water volume and concentration
of electrolytes, especially Na+ and K+.
Aldosterone acts on distal tubules and collecting ducts,
causing a reabsorption of Na+, bicarbonate, and water.
Aldosterone decreases reabsorption of K+ (with H+), then
lost in the urine.
Elevated aldosterone levels may cause alkalosis and
hypokalemia, retention of sodium and water, and increased
blood volume and blood pressure.
Target cells for aldosterone contain mineralocorticoid
receptors that interact with the hormone in a manner
analogous to that of glucocorticoid receptors.
what are the mineralocorticoids actions (Aldosterone)
Help to control the body’s water volume and concentration
of electrolytes, especially Na+ and K+.
Aldosterone acts on distal tubules and collecting ducts,
causing a reabsorption of Na+, bicarbonate, and water.
Aldosterone decreases reabsorption of K+ (with H+), then
lost in the urine.
Elevated aldosterone levels may cause alkalosis and
hypokalemia, retention of sodium and water, and increased
blood volume and blood pressure.
Target cells for aldosterone contain mineralocorticoid
receptors that interact with the hormone in a manner
analogous to that of glucocorticoid receptors.
what is the dosage of CSs
In determining the dosage of adrenocortical steroids, many factors
need to be considered, including:
• Glucocorticoid vs mineralocorticoid activity,
• Duration of action,
• Type of preparation, and
• Time of day when the steroid is administered.
When large doses of the hormone are required for more than 2
weeks, suppression of the HPA axis occurs. Alternate-day
administration of the CS may prevent this A/E.
what are the therapeutic uses of corticosteroids
1) Replacement therapy
2) Treatment of inflammatory diseases:
- such as asthma, osteoarthritis, rheumatoid arthritis, inflammatory
conditions of the skin.
3) Treatment of allergic reactions:
GCs decrease symptoms of asthma, allergic rhinitis, & drug, serum &
transfusion allergic reactions.
- Not curative.
- Inhalation of steroids (ex. Fluticasone, beclomethasone or
triamcinolone) is preferred to oral steroids in treatment of asthma
less A/E.
4) Acceleration of lung maturation:
- To prevent respiratory distress syndrome.
- IM betamethasone or dexamethasone is administered to the pregnant
woman 48 h then 24 h before delivery.
5)some cancers
what are the kinetics of corticosteroids
• GCs can be administered orally, IV, IM, intra-articularly,
topically, via inhalation, or IN spray.
• Greater than 90% of absorbed GCs are bound to plasma
proteins, mostly corticosteroid-binding globulin or albumin.
• Corticosteroids are metabolized by the liver.
The only GC that has no effect on the fetus is prednisone because:
- It is a prodrug that has to be converted to prednisolone. This process
does not occur in the fetal liver.
- Any prednisolone formed in the mother is biotransformed to
prednisone by placental enzymes.
what are the kinetics of corticosteroids
• GCs can be administered orally, IV, IM, intra-articularly,
topically, via inhalation, or IN spray.
• Greater than 90% of absorbed GCs are bound to plasma
proteins, mostly corticosteroid-binding globulin or albumin.
• Corticosteroids are metabolized by the liver.
The only GC that has no effect on the fetus is prednisone because:
- It is a prodrug that has to be converted to prednisolone. This process
does not occur in the fetal liver.
- Any prednisolone formed in the mother is biotransformed to
prednisone by placental enzymes.
what are the side effects of corticosteroids
• Osteoporosis is the most common A/E: due to
- inhibition of calcium absorption from GI.
- inhibition of bone formation.
- Inhibition of sex hormone synthesis.
Recommend coadministration of calcium &
vitamin D.
• Cushing-like syndrome is observed in excess
corticosteroid replacement.
2) Exacerbation of ulcers: high doses of GCs stimulate
gastric acid and pepsin secretion.
3) Weakness: due to myopathy.
4) Increased appetite.
5) Redistribution of body fat, puffy face, hirsutism, acne.
6) Insomnia & emotional disturbances.
7) Glaucoma & cataracts.
8) Hypokalemia.
9) Hyperglycemia.
10) Hypertension.
11) Increased risk of infection.
12) Impaired wound healing.
13) Peripheral edema.
14) Decreased growth in children.
Glucocorticoid withdrawal:
• Sudden discontinuation of these drugs can be a serious
problem if the patient has suppression of the HPA axis.
• Abrupt removal of GC causes acute adrenal insufficiency that
can be fatal.
• This risk, coupled with the possibility that withdrawal might
cause an exacerbation of the disease, means that the dose
must be tapered slowly according to individual tolerance.
• The patient must be monitored carefully
