Nocturnal Urinary Excretion of FSH and LH in Children and Adolescents With Normal and Early Puberty.

Abstract

Clinical use of single serum gonadotropin measurements in children is limited by the pulsatile secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). However, first morning voided (FMV) urine may integrate the fluctuating gonadotropin serum levels. We aimed to evaluate urinary and serum gonadotropin levels according to age, sex, and pubertal stage in healthy children and to assess the clinical use of FMV urinary gonadotropins in children with disordered puberty. Cross-sectional part of the COPENHAGEN Puberty Study and longitudinal study of patients. Population-based and outpatient clinic. Eight hundred forty-three healthy children from the COPENHAGEN Puberty Study and 25 girls evaluated for central precocious puberty (CPP). Clinical pubertal staging, including serum and urinary gonadotropin levels. Urinary gonadotropins increased with advancing age and pubertal development and were detectable in FMV urine before physical signs of puberty. FMV urinary LH correlated strongly with basal (r = 0.871, P < 0.001) and gonadotropin-releasing hormone (GnRH)-stimulated serum LH (r = 0.82, P < 0.001). Urinary LH was superior to urinary FSH in differentiating the pubertal stage. Receiver operating curve analysis revealed that a cut-off standard deviation (SD) score of 2 for urinary LH (IU/L) gave a sensitivity of 75% and a specificity of 92% in predicting a positive GnRH stimulation test (LHmax > 5 IU/L). Urinary concentrations of LH decreased after 3 months of GnRH treatment to levels below +2 SDs. Urinary gonadotropin levels increased before the onset of puberty and were elevated in girls with CPP. We suggest urinary LH as an alternative noninvasive method to improve diagnosing and therapeutic management of children with disordered puberty.