title: Random luteinizing hormone often remains pubertal in children treated with the histrelin implant for central precocious puberty.
abstract: OBJECTIVE
  To investigate the use of random ultrasensitive (US) luteinizing hormone (LH) levels to monitor children being treated with a histrelin implant for central precocious puberty (CPP).
  
  
  METHODS
  This was a prospective, uncontrolled, observational study at a pediatric endocrinology tertiary center. Thirty-three children (26 girls; mean age 7.2 ± 2.5 years) treated with a histrelin implant for CPP were enrolled. A random US LH measurement was obtained at 6 months, and a gonadotropin-releasing hormone analog stimulation test was performed at 12 months. Clinic visits occurred at baseline and at 6-month intervals.
  
  
  RESULTS
  In 59% of the patients (17 of 29), the 6-month random US LH exceeded the prepubertal range of ≤0.3 IU/L. In contrast, gonadotropin-releasing hormone analog stimulation tests revealed complete hypothalamic-pituitary-gonadal axis suppression (peak LH <4 IU/L) in all 31 patients who underwent testing. US LH levels were highly correlated with peak stimulated LH levels. The mean peak stimulated LH level was higher in patients with a pubertal random LH than in those with a prepubertal random LH (1.2 ± 0.5 IU/L vs 0.5 ± 0.1 IU/L; P < .01). No patient had clinical evidence of pubertal progression.
  
  
  CONCLUSIONS
  The random US LH level does not revert to a prepubertal range in more than one-half of patients with a histrelin implant and documented hypothalamic-pituitary-gonadal axis suppression. Long-term studies are needed to elucidate the optimal strategy for monitoring treatment in children with CPP.
authors.affiliation: Section of Pediatric Endocrinology, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Lewis
authors.forename: Erica A
authors.initials: EA
authors.lastname: Eugster
mesh_terms: D002648:Child; D002675:Child, Preschool; D004343:Drug Implants; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011446:Prospective Studies; D011629:Puberty, Precocious / Q000097:blood / Q000188:drug therapy*
chemical_list: D004343:Drug Implants; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; C029256:histrelin