Urinary excretion of immunoreactive gonadotropin-releasing hormone-like material in prepubertal and pubertal children.

A urinary product with immunological similarity to Gn-RH has been quantified by radioimmunoassay. The i-Gn-RH-like material apparently has a (partial) structure consistent with the 5 leads to 9 amino acid sequence of hypothalamic Gn-RH. It inhibits the binding of 125I-Gn-RH to anti Gn-RH serum in a manner parallel to synthetic standard, is absorbed by incubation with anti Gn-RH serum, and comigrates with synthetic Gn-RH on Sephadex column chromatography. The concentration of i-Gn-RH-like material is maximal in pubertal males. The total urinary excretion of this substance is two-fold greater in pubertal subjects of both sexes than in prepubertal children. There is no diurnal variation in the excretion of this material. There are significant positive correlations between the urinary content of iGN-RH-like material and LH and FSH. The site of origin, structure and physiological significance of this immunological product remain to be elucidated.