title: Novel use of endogenous GH-measurement directly after transsphenoidal microsurgery in acromegaly treated with pegvisomant.
abstract: OBJECTIVE
  The GH receptor antagonist pegvisomant is increasingly used as therapy in acromegaly. Pituitary surgery might be indicated on pegvisomant treatment, due to side effects, adenoma growth or intention to cure after primary treatment. This study was initiated to clarify if, and when, GH measurement could be useful postoperatively with an assay specific for endogenous GH that does not cross-react with pegvisomant.
  
  
  METHODS
  This study was designed as a prospective study in 2006 with the German Pituitary Working Group. Only 2 cases with potentially resectable adenomas from the German Pegvisomant Observational Study (GPOS) had been operated. Now with a post-operative follow-up of more than 5 years in these 2 cases, the usefulness of immediate pre-operative GH measurement shortly after pegvisomant treatment was evaluated.
  
  
  RESULTS
  In both patients a steep decline of endogenous GH after transnasal microsurgery could be proven by using the special GH assay after near radical or radical removal, of the GH secreting adenomas respectively. Conventional GH assays showed no effect. GH half-life was more than 20 min in the patient with a small invasive residual adenoma and less than 20 min in the cured patient. Endogenous GH-levels declined to less than 1 ng/ml in the days after surgery in the patient with long-term cure.
  
  
  CONCLUSIONS
  Measurement of endogenous GH in this special subgroup of patients under pegvisomant therapy can be used to decide upon early reoperation. Thus the beneficial effect of pegvisomant on acromegalic symptoms can be kept without interfering with post-operative monitoring of GH levels.
authors.affiliation: Department of Neurosurgery, University Hospital Hamburg, Germany.
authors.forename: D K
authors.initials: DK
authors.lastname: Lüdecke
authors.forename: P A
authors.initials: PA
authors.lastname: Crock
authors.forename: M
authors.initials: M
authors.lastname: Bidlingmaier
authors.forename: F
authors.initials: F
authors.lastname: Schuppert
mesh_terms: D000172:Acromegaly / Q000097:blood / Q000188:drug therapy* / Q000601:surgery; D000236:Adenoma / Q000097:blood / Q000188:drug therapy / Q000601:surgery*; D013507:Endocrine Surgical Procedures / Q000379:methods; D005260:Female; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000097:blood / Q000188:drug therapy / Q000601:surgery*; D019382:Human Growth Hormone / Q000031:analogs & derivatives* / Q000097:blood* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011379:Prognosis; D013101:Sphenoid Sinus / Q000601:surgery
chemical_list: D019382:Human Growth Hormone; C406545:pegvisomant