Corticosteroids 3&4 Flashcards
what hormones does the hypothalamus produce?
oxycontocin
ADH
where are hormones from the hypothalamus transported and stored? what happens after?
hormones are transported and stored to the posterior pituitary for storage
this directcs the posterior pituitary to release hormones
what controls the pituitary gland?
controlled by the hypothalamus
where is the pituitary gland?
•Located at the base of the brain–Protected by a bony structure called the sella turcica
–The optic chiasmis located just above the pituitary gland
what are the two lobes of the pituitary gland?
anterior lobe
posterior lobe
what is the function of the anterior lobe in the pituitary gland?
GH- stimulates increase in size of muscles and bones
luteinzing hormone- females stimulates ovulation and oestrogen production
males-stim testosterone production
adrenocorticotropic-stim the adrenal cortex to release its hormones
prolactin-stimulates milk production
thyroid stim -stimulates the thyroid gland to release its hormones
follicle stimulation
females: stim oestrogen production and maturation of the ova
males-stimulates sperm production
how much do the human adrenals weigh?
8-10g
what does the adernal gland comprise of?
outer cortex with 3 zones (reticularis, fasciculta and glomerulosa) producing steroids
-inner medulla that synthesizes, and secretes catecholamines
what are the basal daily secretions of the glucocorticoids?
cocrtisol 5-30mg
corticosterone 2-5mg
what are the basal daily secretions of mineralocorticoids?
aldosterone 5-150mcg
11-deoxycorticosterone trace
what are the basal daily secretions of the sex hormones?
androgen-DHEA- 15-30mg
progestogen-progesterone 0.4-0.8mg
oestrogen-oestradiol-trace
what is the pre cursor of all adrenal steroids?
cholesterol metabolism
cholesterol and its metabolites are the substrates for multiple enzymes
what are the critical targets in cholesterol metabolism?
Cholesterol desmolasen and the17α-and 11β-hydroxylases are critical pharmacologic targets.
what is cholesterol the precursor of?
vitamin D and bile acids
what are the 14 pharmacological actions of corticosteroids?
- Carbohydrate
- Protein
- Lipid
- Electrolyte & water
- CVS
- Sk. Muscle
- CNS
- Stomach
- Blood
- Anti-inflammatory
- immunosuppressant
- Respiratory system
- Growth & Cell Division
- Calcium metabolism
what are the main metabolic effects of glucorticosteroids?
carbohydrate and protein metabolism
what happens in carb and protein metabolism due to steroids?
• INC Gluconeogenesis –Peripheral actions (mobilize AA & glucose and glycogen) –Hepatic actions Tendancy for hyperglycaemia •DEC Peripheral utilization of glucose • INC Glycogen deposition in liver overall dec in protein synthesis
what may a decrease in protein synthesis cause?
increased protein breakdown, particularly in the muscle
this can lead to tissue wasting
what effect does glucocorticoids hae on the cAMP-dependent lipplytic response?
such hormones cause lipase activation through a cAMP dependent kinase
what effect is seen when large doses of glucocorticoids are given over a long period of time?
redistribution of fat
-buffalo hump
moon face
these are characterictics of cushing’s syndrome
what does lipid metabolism also promote?
promotes adipokinetic agents activity
how is the electrolyte and water balance affected by glucocortcoids?
aldosterone is important
act on the distal tubule and collecting duct of the kidney
-increase na+ reabs
- increase urinary excretion of k+ and h+
how does glucocorticoids affect the cardiovascular system?
- Restrict capillary permeability
- Maintain tone of arterioles
- Myocardial contractility
what is the effect on skeletal muscles?
it is needed for maintaining the normal function of skeletal muscle
addison’s disease: weakness and fatigue- inadequacy of circulatory system
prolonged use: skeletal muscle wasting system- steroid myopathy
what is the effect on the CNS?
direct effect on mood, behavior and brain excitability
indirect effect on glucose maintenance, circulation and electrolyte balance
what is the release of glucocrticoids dependent on?
the amount of circulating ACTH
when is the plasma cortisol levels highest?
in the morning
what effects does glucocortcoids have on the stomach?
aggravate peptic ulcer
this may be due to:
-increase in acids and pepsin secretion
-decrease in immune response to h.pylori
what effects do steroids have on the blood?
RBC: Hb & RBC content (erythrophagocytosis)
WBC: decrease Lymphocytes, eosinophils, monocytes, basophils
increase Polymorphonuc leocytes
what are the anti-inflamatory and immunosuppressive effects of glucortcoids?
suppresses all types of h y persensitivity and allergic phenomeon
what happens with a high dose for the anti-inflam and immunosuppressive effects?
interferes with all steps of the immunological response
causes greater suppression of CMI
transplant rejection
what are the action on inflam cells?
dec egress of neutrophils from blood vessels
•activation of neutrophils, macrophages and mast cellssecondary to decreased transcription of the genes forcell adhesion factors and cytokines
•decreased overall activation of T-helper (Th) cells
•dec clonal proliferation of T cells, and a ‘switch’ from theTh1 to the Th2 immune response
•decreased fibroblast function, less production of collagen and glycosaminoglycans, and, under some circumstances, reduced healing and repair.
what are the actions on the mediators of inflam and immune responses?
• DEC Production of prostanoids through reduced expression of cyclo-oxygenase-2
• DEC Generation of many cytokines, including IL-1, IL-2, IL-3,IL-4, IL-5, IL-6, IL-8, TNF-α, cell adhesion factors and granulocyte–macrophage colony-stimulating factor.These are largely secondary to inhibition of genetranscription
• DEC In the concentration of complement components inthe plasma
• DEC Generation of induced nitric oxide by nitric oxidesynthase 2 (NOS2
DEC Histamine release from basophils and mast cells
• DEC Immunoglobulin G (IgG) production
• INC Synthesis of anti-inflammatory factors such as IL-10, IL-1-soluble receptor and annexin-1