Flashcards in Steroids Deck (25):
What is respiratory disease?
Term given to diseases that affect organs and tissues involved in gaseous exchange
What is asthma?
Inflammation of the airways- bronchi are inflamed and sensitive.
Irritants trigger an asthma attack- smooth muscle contracts and reduce airflow.
What is COPD?
Chronic obstructive pulmonary disease- collection of COAD, emphysema and chronic bronchitis.
primary cause is smoking
Inflammation leads to scarring in the lungs
Damage to the lungs causes breakdown of alveolar structure and results in emphysema.
what are the goals of Respiratory disease treatment?
-Reduce inflammation and swelling in the airways
-Smooth muscle constriction
describe the general steroid structure?
4 cycloalkane ring structure with 3 cyclohexane rings and 1 cyclopentane ring
how is variation of steroids achieved?
differing functional groups attached to 4-ring core and oxidation state of the rings
Name a steroid that functions as a dietary fat?
What steroid is mainly used as a male sex hormone?
What is a hormone?
chemical messenger released by a cell/gland in one part of the body that can affect cells in another part of the body
what are the roles of steroid hormones within the body?
Development of sexual characteristics
What are the groups of steroids within the body, and name the steroids within these groups.
corticosteroids (produced in adrenal cortex): Glucocorticoids + mineralocorticoids
Sex steroids (produced in different locations):Androgens, Oestrogens and progestogens
what are the physiological roles of corticosteroids?
-Produced in the adrenal cortex(adrenal gland)
-Regulate immune function, stress response and metabolism
-Include glucocorticoids (cortisol) and mineralocorticoids (aldosterone)
What are the physiological roles of Sex steroids?
-produced in the Ovaries, testes and adrenal gland
-Interact with estrogen or androgen receptors
-differentiate sex and support reproduction
-Androgens (testosterone), oestrogens (estradiol) and progestogens (progesterone)
why is cholesterol an important steroid?
Cholesterol acts as a synthetic precursor which is involved in the synthesis of steroid hormones and vitamin D.
Also functions to decrease cell membrane fluidity.
Explain the process of steroidogenesis?
-synthesis of steroids
-steroids are generated from cholesterol
-cleavage and modification is carried out by the cytochrome P450 family.
-results in formation of many different steroid types.
-Metabolism via cytochrome P450 family, formation of bile acids + elimination from liver as bile
What are steroid drugs referred to as due to there MOA?
Anti-inflammatory drugs or immuno-suppresive drugs
What is the steroid MOA as an anti-inflammatory agent?
1)steroid crosses plasma membrane
2)steroid binds to receptor and displaces HSP90
3)HSP90 acts to facilitate steroid receptor functioning
4)Steroid receptor complex forms a dimer + enters nucleus
5)Once in nucleus complex can function several ways
6)A- cause transcription/translation of proteins such as IKB
6.1)IKB acts as an inhibitor of NFKB, NFKB causes the production of PRO-inflammatory proteins, IKB stops NFKB function and therefore decreases expression of pro-inflammatory proteins.
7)B- Directly interact with NFKB to supress cytokine synthesis
what is the steroid MOA in immune suppresion?
Steroids directly affect cells of the immune system to suppress pro-inflammatory responses
-Inhibit production of pro-inflammatory cytokines such as IL-2, TNF, IL-1beta
-promote production of anti-inflammatory cytokines such as IL-10
-Promote apoptosis of T-cells, macrophages and dendritic cells resulting in a decreased immune response
-reduction in NK cell cytotoxicity
-Reduce expression of cell surface molecules important for T-cell activation
Also regulates AA metabolism
-increase transcription and translation of lipocortins which results in phospholipase A2 suppression and COX expression is also suppressed.
what are the methods of steroid treatment for someone suffering with chronic asthma?
Inhaled steroids-Budesonide, Beclometasone diproprionate and fluticasone proprionate
what are the methods of steroid treatment for someone suffering with Acute asthma?
Discuss the steroid Beclometasone diproprionate
-Prodrug form of beclometasone
-generally administered as aerosol
-Metaboilised by esterase enzymes which are present in most tissues
-Mainly excreted in faeces
-t1/2 = 2.8 hours
Discuss the steroid fluticasone proprionate
-Administered by inhalation
-Metabolised in liver by cytochrome P450 system
-mainly excreted in faeces
-t1/2 7.8 hours
Discuss the steroid
-administered by inhalation
-subject to high FPM (80-90%)
-excreted in urine and faeces
-t1/2 2.0-3.6 hours
Discuss the steroid prednisolone
-used in treatment of wide range of inflammatory diseases
-oral administration (acute asthma)
-Readily absorbed in GI tract
-Excreted in urine
-t1/2 2-3 hours