18-01-2013, 09:37 AM
ADRENOCORTICOSTEROIDS
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The adrenal glands are two small structures situated on top of each kidney.
they consist of two distinct regions:
an outer layer (the adrenal cortex) and
the inner part (adrenal medulla)
The adrenal medulla releases: adrenaline and noradrenaline.
The cells of the adrenal cortex secrete a variety of steroid hormones
Adrenal Hormones
Aldosterone is the primary and most potent mineralocorticoid
Conserves sodium through its action on cells in distal nephron
Regulated by the renin-angiotensin-aldosterone system
Effects of Mineralocorticoids
Conserve sodium and water and eliminating potassium
Secretion of aldosterone is largely controlled by kidneys
Inadequate secretion of aldosterone causes hyperkalemia, hyponatremia and ECF volume deficit. Hypotension, shock and death may ensue.
Excessive secretion of aldosterone produces:
hypokalemia
hypernatremia and
Excess ECF volume (water intoxication)
Edema and hypertension will result.
Glucocorticoids
hydrocortisone(cortisol) is the most abundant glucocorticoid .
It possesses some mineralocorticoid activity as well.
Cortisone is less potent and is converted to hydrocortisone by liver
Physiological effects of Glucocorticoids
Anti-inflammatory & immunosuppressive effects
dramatically reduce the manifestations of inflammation.
inhibit the functions of tissue macrophages & other antigen presenting cells.
They influence the inflammatory response by reducing activation of phospholipase A2 and thus decreasing the prostaglandin, leukotriene, & platelet activating factor synthesis
Therapeutic Uses of Glucocorticoids
Replacement Therapy In Addison's disease
Chronic adrenocortical insufficiency is characterized by weakness, fatigue, weight loss, hypotension, hyperpigmentation, and inability to maintain the blood glucose level during fasting
Autoimmune adrenal disease and infections are the major etiologic factors of primary adrenal insufficiency
Physiologic actions of estrogens
Ovary: estrogen affects the ovary through indirectly influencing the secretion of gonadotrophin
Uterus: it affects the ‘proliferative phase’ of the endometrium and also increases the growth and sensitivity of myometrium for oxytocin.
Cervix: it makes cervical mucus thin and alkaline
Breast: estrogen causes the growth of gland and duct system
Anterior pituitary: estrogen inhibit release of gonadotrophins (FSH, LH)
Therapeutic uses of estrogen
contraceptive in combination with progestins
functional uterine bleeding
dysmenorrhea, alleviation of menopausal disorder
osteoporosis
replacement therapy in ovarian failure
Mechanism of action
Oral contraceptives seem likely to decrease pituitary responsiveness to GnRH.
estrogen inhibits secretion of FSH via negative feedback on the anterior pituitary and thus suppresses development of the ovarian follicle
progestins inhibits secretion of LH and thus prevents ovulation; it also makes the cervical mucus less suitable for the passage of sperm
Estrogen and progestins act in concert to alter the endometrium in such a way as to discourage implantation.
Common adverse effects include:
Increased incidence of thrombosis and embolism, attributed to the estrogen component in particular.
weight gain, owing to fluid retention or an anabolic effect or both
mild nausea, flushing, dizziness, depression or irritability
Amenorrhea of variable duration on cessation of taking the pill