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Shinelkimo
Joined: 25 Apr 2007
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 Posted: Thu May 24, 2007 2:52 am Post subject: Adrenal tumours |
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Q: Adrenal tumours causing female hirsutism are characteristically associated with (31)
290. the absence of diurnal cortisol variation |
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cpeedahsa
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Joined: 21 Apr 2007
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| Posted: Thu May 24, 2007 4:01 am Post subject: Re: Adrenal tumours |
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[quoteQ: Adrenal tumours causing female hirsutism are characteristically associated with
290. the absence of diurnal cortisol variation[/quote]
True
http://www.endocrinology.med.ucla.edu/cushing's_syndrome.htm
| Quote: | Tests to distinguish Cushing’s from pseudo-Cushing’s
Diurnal variation: Normally, cortisol levels peak at 4-8 a.m., and decline through the day to a nadir (< 50-80% of a.m. values) at midnight to 2 a.m. Patients with true CS lose this diurnal variation, whereas it is preserved in pseudo-Cushing’s. A midnight cortisol > 7.5 µg/dl indicates CS, while a value < 5 µg/dl rules it out. Must be drawn from an indwelling catheter after a 3 hour fast and 2 hours of rest. |
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EMAK
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| Posted: Thu May 24, 2007 4:37 am Post subject: |
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| I think it is ass. with elevated level od androgen which will cause negative feed back to the hypothalamus with lowering of releasing hormons, so I agrre ther will be loss of diurnal variation. |
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Nick Raine-Fenning
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Joined: 27 May 2006
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Location: Nottingham
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| Posted: Thu May 24, 2007 3:28 pm Post subject: |
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Absolutely ... any peripheral source of a hormone under hypothalamic-pituitary feedback control will have a disordered production and variation.
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cpeedahsa
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| Posted: Thu May 24, 2007 6:42 pm Post subject: |
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| EMAK wrote: | | I think it is ass. with elevated level od androgen which will cause negative feed back to the hypothalamus with lowering of releasing hormons, so I agrre ther will be loss of diurnal variation. |
There is indeed a loss of diurnal variation in adrenal tumors causing hirsutism.
However, The above explanation is not quite applicable though.
Normally, cortisol is secreted episodically with a diurnal rhythm paralleling the secretion of ACTH. Patients with Cushing's syndrome occasionally have a normal morning cortisol but lack normal diurnal decline in cortisol production, such that the midnight plasma cortisol levels are above normal and the total 24-h cortisol production is elevated. Patients with true CS lose this diurnal variation, whereas it is preserved in pseudo-Cushing’s.
Inhibitory feedback (which in turn means intact HPA axis and intact hypothalamic regulation of adrenal hormone secretion)-- would result in a total decrease in the levels of hormones whilst actually retaining the diurnal variation.
In case of adrenal tumors(Cushing's Syndrome) --there is no diurnal variation of cortisol.
Last edited by cpeedahsa on Mon May 28, 2007 11:48 pm; edited 6 times in total |
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rpwalavalkar
Teale Fenning Administrator
Joined: 20 Jul 2006
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| Posted: Fri May 25, 2007 12:07 am Post subject: |
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agree with everyone else ... True
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EMAK
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| Posted: Fri May 25, 2007 4:28 am Post subject: |
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| I know well the difference bet. cushing disease and cushing syndrome and dexamethazone supression test will differentiate between both, but still I think both of them ass. with increase cortisol secretion and loss of diurnal variatio. |
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