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|Title:||17-hydroxylase/C17,20-lyase (CYP17) is not the enzyme responsible for side-chain cleavage of cortisol and its metabolites|
|Authors:||Shackleton, Cedric H. L.|
Neres, Marcos S. [UNIFESP]
Hughes, Beuerly A.
Stewart, Paul M.
Kater, Claudio E. [UNIFESP]
Universidade Federal de São Paulo (UNIFESP)
|Citation:||Steroids. New York: Elsevier B.V., v. 73, n. 6, p. 652-656, 2008.|
|Abstract:||The question addressed in this study was the nature of the enzyme required to remove the side-chain of 17-hydroxycorticosteroids, leading in the case of cortisol to the excretion of 11 beta-hydroxyandrosterone, 11-oxo-androsterone and the corresponding etiocholanolones. We questioned whether it could be CYP17, the 17-hydroxylase/17,20-lyase utilized in androgen synthesis. the conversion of exogenous cortisol to C-19 steroids in patients with complete 17-hydroxylase deficiency (17HD) was studied rationalizing that if CYP17 was involved no C-19 steroids would be formed. the urinary excretion of the four 11-oxy-C-19 steroids as well as many of the major C-21 cortisol metabolites were measured by GC/MS. Our results showed that the conversion of cortisol to C-19 steroids was normal in 17HD indicating that a currently unidentified enzyme must be responsible for this transformation.A secondary goal was to determine to what extent 11-oxy-C-19 steroids were metabolites of cortisol or adrenal synthesized 11 beta-hydroxyandrostenedione. Since cortisol-treated 17HD patients cannot produce androstenedione, all C-19 11-oxy-metabolites excreted must be derived from exogenous cortisol. the extent to which 17HD patients have lower relative excretion of C-19 steroids should reflect the absence of lip-hydroxyandrostenedione metabolites. Our results showed almost all of 11-oxo-etiocholanolone and 11 beta-hydroxyetiocholanolone were cortisol metabolites, but in contrast the excretion of lip-hydroxyandrosterone was less than 10% that of normal individuals, indicating that in excess of 90% must be a metabolite of 11 beta-hydroxyandrostenedione. (C) 2008 Elsevier Inc. All rights reserved.|
|Appears in Collections:||Em verificação - Geral|
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