title: Effect of enalapril on exaggerated erythropoietin response to phlebotomy in erythrocytosic renal transplant patients.
abstract: BACKGROUND
  Exaggerated erythropoietin (EPO) response to phlebotomy regardless of the baseline EPO levels have been shown in patients with post-transplant erythrocytosis (PTE) and administration of angiotensin-converting enzyme inhibitors (ACE-1) seems to be effective in controlling PTE. However, the mechanism of this ACE-1 induced reduction in haematocrit (Hct) is not well known. Although some authors have suggested that ACE-1 may reduce EPO secretion, this is still controversial. The aim of the present study was to assess the effect of a single dose ACE-1 on exaggerated EPO response to phlebotomy.
  
  
  METHODS
  In this study, we compared serum EPO and renin (PRA) levels of 10 PTE patients, 10 non-PTE patients and 10 healthy blood donors before and after phlebotomy. The effects of a single dose of ACE-1 (enalapril, 5 mg p.o.) in PTE patients were also evaluated in the second phlebotomy.
  
  
  RESULTS
  While the mean basal serum EPO level was significantly higher in the PTE group than the other two groups (P<0.01), the mean basal PRA levels did not differ significantly between these groups. Serum EPO and PRA levels increased significantly after the phlebotomy (P<0.001) and exaggerated EPO response to phlebotomy was suppressed by single dose enalapril (P<0.001) in the PTE patients.
  
  
  CONCLUSIONS
  The present study has shown that the renin angiotensin system plays an important role in EPO formation and the Hct lowering effect of the ACE-1 is through reduction of EPO in PTE patients.
authors.affiliation: Department of Nephrology, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: C
authors.initials: C
authors.lastname: Usalan
authors.forename: Y
authors.initials: Y
authors.lastname: Erdem
authors.forename: M
authors.initials: M
authors.lastname: Cağlar
authors.forename: B
authors.initials: B
authors.lastname: Altun
authors.forename: M
authors.initials: M
authors.lastname: Arici
authors.forename: M
authors.initials: M
authors.lastname: Bakkaloğlu
authors.forename: U
authors.initials: U
authors.lastname: Yasavul
authors.forename: C
authors.initials: C
authors.lastname: Turgan
authors.forename: S
authors.initials: S
authors.lastname: Cağlar
mesh_terms: D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D004656:Enalapril / Q000627:therapeutic use*; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D018962:Phlebotomy; D011086:Polycythemia / Q000097:blood / Q000188:drug therapy*; D011446:Prospective Studies; D012083:Renin / Q000097:blood
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004921:Erythropoietin; D004656:Enalapril; D012083:Renin