confusedoc
Forum Junior
Topics: 10
Posts: 43
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can someone pls explain the metyrapone test 2 me. is the test used in both hypo and hypercortisolism? and how r the tests interpreted. goljan notes have left me kinda confused
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| Ig F
Forum Elite
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Posts: 440
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well alwayz remember one rule......whenever there is an excess of some hormone we do suppression test and for deficient hormones we do stimulation testz....
now METYRAPONE inhibitz 11 hydroxylase....resulting in the decrease in cortisol.....now u knw tht cortisol has an inhibitory effect on ACTH secretion...so in the absence of cortisol there is an increase in ACTH nd 11 deoxycortisol.now here is the interpretation of this test..if there is a lack of increase in ACTH AND 11 DEOXYCORTISOL, this showz tht the defect is in the hypothalamic pituitary axis....bcoz the decrease in the cortisol level has failed to increase the amount of ACTH......
now the second interpretation if the ACTH has increased but 11 deoxycortisol hasnt increased this showa the problem lies in the adrenal bcos despite the stimulation from high levelz of ACTH,adrenalz hv failed to produce de oxycortisol....
well this was for hypocortisolism...we did stimulation test....
remember one thing cortisol and ACTH r inter related.......if cortisol goes high theACTH goes low BUT IF ACTH goes high it increases cortisol......
now here is the explanation for metyrapone test in cases of hypercortisolism......which showz high level of cortisol but low levelz of ACTH.....so for high levelz of cortisol we r doing suppression test..now in cases of hypercortisolism if metyrapone is given it decreases the amount of cortiso as usual but ACTH will also not be increased due to prolong inhibiton by high levelz of cortisol...if in case the acth or 11 deoxycortisol icreases this meanz tht pituitary tumor is responsive to drop in the levelz of cortisol but incase of ectopic cushingz there will be no cahnge bcoz the tumour is ectopically producing ACTHwhich is causing hypercortisolism.......
i knw thtz a very lengthy explanation but it will be easier for u to understand.take care
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| confusedoc
Forum Junior
Topics: 10
Posts: 43
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thanx a lot fatimahussain. these words of gratitude shudve come right away, bt had some health problem, so i couldnt reply.
thanx once again 2 u and all others in this forum.
keep going 
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| MRMAVERICK
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