Abstract: | Serum levels of human chorionic gonadotropin (hCG)-like substance and human luteinizing hormone (hLH) in healthy children aged 4–17 years were measured by sensitive enzyme immunoassay techniques. In enzyme immunoassay for hCG-like substance, minimal cross-reaction with hLH was observed. In enzyme immunoassay for hLH, there was a considerable cross-reaction with hCG. However, serum levels of hCG-like substance were below 0.08 IU/liter or less than one fourth of serum hLH levels. Therefore, values obtained for serum hLH levels were considered to be reliable. Serum levels of hCG-like substance increased with increasing ages in some children, with the highest level 0.23 IU/liter in a male aged 14 years. Serum hLH levels were 0.02–0.7 IU/liter in children aged 4–8 years, elevated during the ages of 9 to 11 years, reaching the range of 3–27 IU/liter in children aged 12–17 years. The sensitive enzyme immunoassay technique used in this study will be useful for the detection of hypogonadotropic hypogonadism in children. |