clar697
Forum Guru
Topics: 190
Posts: 199
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A 15-year-old girl is virilizing adrenal hyperplasia. Increased serum concentrations of 11-deoxycorticosterone have resulted in hypernatremia, hypokalemia, and hypervolemia. Serum ACTH concentration is increased, but serum aldosterone concentration is decreased. Administration of dexamethasone normalizes the ACTH, 11-deoxycorticosterone, aldosterone, and androgen concentrations. Which of the following labeled enzymes is most likely to be defective in this patient?
A) Cholesterol side-chain cleavage enzyme to yield pregnenolone
B) 17-alpha-hydroxylase (converts pregnenolone to 17-hydroxypregnenolone)
C) C 17-20 lyase (converts 17-hydroxypregnenolone to dehydroepiandrosterone)
D) 3-beta-hydroxysteroid dehydrogenase: delta 6,6 isomerase
E) 21-hydroxylase
F) 11-beta-hydroxylase
G) 18-hydroxylase
H) 18-hydroxydehydrogenase
I) 17-ketoreductase
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| cooolguy
Forum Newbie
Topics: 0
Posts: 25
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cant believe i forgot this stuff =(
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| maoudoody
Forum Guru
Topics: 56
Posts: 869
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actually it is better to be posted in the physio or patho section!!!!!
dont know
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| alirizvi
Forum Elite
Topics: 22
Posts: 372
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11 beta hydroxylase ?
This is off topic but might help some people, because everyone seems to forget adrenal enzymes, u only need to know the 3 main ones anyways i hope this helps..
When it says "1" = INCREASE ( make an up arrow ^^ )
In the 1st column u put blood pressure and in the second u put steroids.
The rest everything is same, they all have inc cortisol dec acth etc..
21 Normal bp Inc steroids syn
11 Inc. bp Inc steroid syn
17 Inc. bp normal steroid syn
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| a3112
Forum Elite
Topics: 7
Posts: 265
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hey clar! can u tell me what the last 3 enzymes do?? may be then i can tell the answer..
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| Mike99
Forum Junior
Topics: 11
Posts: 36
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one more try? here's the graph
Attached Files:
Doc2-1.doc (107 KB, 10 downloads)
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| a3112
Forum Elite
Topics: 7
Posts: 265
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11 b hydroxylase def expalins everything except for the normalisation of aldosterone after dexa.. 
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| DRFP
Forum Guru
Topics: 40
Posts: 722
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I have no Idea the Answer key says H but I also think F
Its F look here : http://www.vivo.colostate.edu/hbooks/pathphys/end...
Attached Files:
10.jpg (423 KB, 13 downloads)
Edited by DRFP on 11/02/08 - 08:33 PM
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