title: The utility of the IGF-I generation test in children with chronic kidney disease.
abstract: BACKGROUND
  To determine if the insulin-like-growth factor (IGF-I) generation test is a marker for growth hormone (GH) sensitivity in children with chronic kidney disease (CKD).
  
  
  METHODS
  This was a randomized cross-over study in which children with CKD received low-dose (0.025 mg/kg/day) and high-dose (0.05 mg/kg/day) GH therapy in the framework of a 7-day IGF-I generation test. Blood samples were collected on day 1 (D1; pre-dose) and on day 8 (D8; post 7 doses) of GH therapy. All subjects received GH for 12 months at 0.05 mg/kg/day. Serum IGF-I was measured by radioimmunometric assay. Normative historic data from healthy children and those with idiopathic short stature were used for comparison.
  
  
  RESULTS
  Sixteen subjects (age 2-13 years) with creatinine clearances of between 25 and 75 ml/min/1.73 m(2) were enrolled. Annualized height velocity for all subjects was 10.3 ± 1.1 cm/year (mean ± standard deviation), with an annual change in height Z score of 0.7 ± 1.0. No correlation was found between the generated serum IGF-I levels (D8 - D1) and creatinine clearances, and with changes in height Z scores. Serum IGF-I levels on D1 and D8 in CKD subjects were lower than normative data, but with adequate IGF-I generation on D8.
  
  
  CONCLUSIONS
  Children with CKD were able to respond to GH therapy with both growth and an increase in serum IGF-I levels, but the IGF-I generation test was not a good predictor of growth response in this cohort.
authors.affiliation: Division of Nephrology and Hypertension, Department of Pediatrics, Oregon Health & Science University, 707 SW Gaines Rd, Mail Code: CDRCP, Portland, OR, 97239, USA, aluzria@ohsu.edu.
authors.forename: Amira
authors.initials: A
authors.lastname: Al-Uzri
authors.forename: Rita D
authors.initials: RD
authors.lastname: Swinford
authors.forename: Thuan
authors.initials: T
authors.lastname: Nguyen
authors.forename: Randall
authors.initials: R
authors.lastname: Jenkins
authors.forename: Anthony
authors.initials: A
authors.lastname: Gunsul
authors.forename: Svetlana S
authors.initials: SS
authors.lastname: Kachan-Liu
authors.forename: Ron
authors.initials: R
authors.lastname: Rosenfeld
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D001827:Body Height / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D005260:Female; D006130:Growth Disorders / Q000097:blood / Q000188:drug therapy / Q000209:etiology; D019382:Human Growth Hormone / Q000008:administration & dosage; D006801:Humans; D015592:Immunoradiometric Assay; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D018579:Patient Selection; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D016896:Treatment Outcome; D014481:United States; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; C583557:IGF1 protein, human; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I