Urinary excretion of immunoreactive luteinizing hormone-releasing hormone-like material and gonadotropins at different stages of life

LHRH-like immunoreactivity (IR LHRH) excreted in human urine spontaneously or after iv injection of LHRH was studied. It was characterized by gel filtration on carboxymethyl-cellulose and RIA using two antisera with different affinities for LHRH fragments. From these studies, it was suggested that the material excreted after iv injection of 1-10 LHRH was heterogeneous and contained at least 1-10 and 2-10 LHRH. In contrast the properties of endogenous urinary material were consistent with the absence of detectable intact decapeptide and the presence of 2-10 nonapeptide of LHRH as a major excretory product. In 24-h urines obtained from 292 normal subjects, IR LHRH, FSH, and LH were assayed and related to their chronological ages. The mean level of IR LHRH was found to be the lowest in male and female infants (3.2 and 2.9 ng/24 h), and to rise gradually in prepubertal boys and girls until 11 yr and markedly in postmenopausal women (49 ng/24 h). No significant differences of urinary IR LHRH excretion appeared between the last prepubertal aged subject and pubertal or adult subjects. A significant positive correlation between urinary IR LHRH and both FSH and LH was observed in prepubertal boys and girls, in pubertal boys, and (for LH only) in adult males. No correlation was observed in infants of either sex or in pubertal, adult, or postmenopausal females.