title: Increased cortisol metabolites and reduced activity of 11beta-hydroxysteroid dehydrogenase in patients on hemodialysis.
abstract: BACKGROUND
  Patients with renal failure have symptoms assumed to be attributable to the accumulation of toxic endo- or xenobiotics. Most of these molecules, especially those with a molecular weight>300 D, have not been identified. In addition to excretion, the kidney is involved in some defined metabolic processes. In the cortical collecting duct, the enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) interconverts cortisol (F) and cortisone (E), and the metabolites of these glucocorticoids, tetrahydrocortisol (THF), 5alpha-tetrahydrocortisol (5alpha-THF) and tetrahydrocortisone (THE), are excreted in urine. We hypothesized that first, these metabolites accumulate and second, their concentration pattern changes in patients on hemodialysis.
  
  
  METHODS
  THF, 5alpha-THF, THE, F and E were measured in plasma of 63 patients on dialysis and in 34 healthy controls by gas-chromatography-mass spectrometry (GC/MS). In 11 patients, the metabolite clearance was determined during high flux hemodialysis by using a population pharmacokinetic approach.
  
  
  RESULTS
  Mean plasma concentrations of THF, 5alpha-THF and THE were more than five times higher and those of E lower in patients than in controls. The ratios of (THF + 5alpha-THF)/THE and F/E were increased in patients, indicating a reduced activity of 11beta-HSD2. Intradialytic clearances were between 120 and 300 mL/min and not sufficient to normalize the steroid concentrations.
  
  
  CONCLUSIONS
  Patients on hemodialysis exhibit pronounced increases in THF, 5alpha-THF and THE concentrations in plasma with insufficient removal during dialysis. Due to a reduced 11beta-HSD2 activity, an abnormal pattern of the concentrations of these cortisol and cortisone metabolites is observed. Since many signs and symptoms in uremic patients resemble those observed in subjects with glucocorticoid excess, the clinical relevance of the high concentrations of these glucocorticoid metabolites deserves further investigation.
authors.affiliation: Division of Nephrology and Hypertension, University of Berne, Berne, Switzerland.
authors.forename: Verena
authors.initials: V
authors.lastname: N'Gankam
authors.forename: Dominik
authors.initials: D
authors.lastname: Uehlinger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Dick
authors.forename: Brigitte M
authors.initials: BM
authors.lastname: Frey
authors.forename: Felix J
authors.initials: FJ
authors.lastname: Frey
mesh_terms: D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D000328:Adult; D000368:Aged; D003348:Cortisone / Q000032:analysis / Q000097:blood / Q000652:urine; D015314:Dialysis Solutions / Q000737:chemistry / Q000378:metabolism; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000097:blood* / Q000652:urine; D006913:Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology; D007676:Kidney Failure, Chronic / Q000201:enzymology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D014511:Uremia / Q000201:enzymology / Q000628:therapy
chemical_list: D015314:Dialysis Solutions; D006913:Hydroxysteroid Dehydrogenases; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; C468387:HSD11B2 protein, human; D003348:Cortisone; D006854:Hydrocortisone