title: [Effects of activity of 11β-hydroxysteroid dehydrogenase type 2 on serum potassium levels in Cushing's syndrome patients].
abstract: OBJECTIVE
  To explore the effects of different forms of glucocorticoid excess on cortisol/cortisone ratio and to reveal the mechanisms of hypokalemia in Cushing's syndrome patients.
  
  
  METHODS
  The levels of urinary free cortisol (UFF) and urinary free cortisone (UFE) were determined in 6 adult patients with ectopia adrenocorticotropic hormone (ACTH) syndrome, 6 normal serum level of potassium adults with hypercortisolism due to adrenal tumor, 5 hypokalemic adults with hypercortisolism due to adrenal tumor and 6 healthy volunteers using high-performance liquid chromatography plus tandem mass spectrometry (LC-MS/MS).
  
  
  RESULTS
  For 4 groups, the results of UFF+UFE were (2 787 ± 820), (689 ± 163), (697 ± 120) and (70 ± 27)µg/L and UFF/UFE ratio 2.98 ± 0.35, 1.03 ± 0.42, 2.24 ± 0.37 and 0.42 ± 0.20 respectively. The values of UFF+UFE had no statistical difference between normal and low levels of serum potassium adults with hypercortisolism. And the ratio of UFF/UFE of hypokalemic adults with hypercortisolism was significantly higher than that of normal serum level of potassium adults with hypercortisolism. It suggested that the deficiency of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD 2) was present in hypokalemic adults with hypercortisolism.
  
  
  CONCLUSIONS
  Due to a deficiency of 11β-HSD2, active cortisol can not be transformed into inactive cortisone in some patients with ACTH-independent Cushing's syndrome.
authors.affiliation: Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Penghu
authors.initials: P
authors.lastname: Lian
authors.affiliation: Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China; Email: lihanzhong@medmail.com.cn.
authors.forename: Hanzhong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Ji
mesh_terms: D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D000310:Adrenal Gland Neoplasms; D000324:Adrenocorticotropic Hormone; D003348:Cortisone; D003480:Cushing Syndrome; D005938:Glucocorticoids; D006801:Humans; D011188:Potassium; D053719:Tandem Mass Spectrometry
chemical_list: D005938:Glucocorticoids; D000324:Adrenocorticotropic Hormone; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D011188:Potassium; D003348:Cortisone