The metabolic serum clearance of GnRH. Relationship to age, sex and male puberty.

Abstract

The MCR of constantly infused synthetic GnRH (1.53 micrograms/min) was studied in relation to age, sex, and male sexual maturation. GnRH was determined by a radioimmunoassay using a specific GnRH antiserum and 125I-GnRH, prepared by the chloramine T technique and purified on Sephadex G 25. Serum LH and FSH were measured by RIA. The results (mean values +/- SEM) of MCR expressed here as ml/min/1.86 m2 showed a statistically significant difference: infants (6-13 yrs) 1170 +/- 79, sexually mature males (22-29 yrs) 639 +/- 28, elderly men (64-79 yrs) 520 +/- 38, sexually mature females (20-24 yrs) follicular phases: 1354 +/- 90, luteal phases: 1736 +/- 242, postmenopausal women (53-74 yrs) 598 +/- 45. We found a linear negative correlation between serum LH and MCR of GnRH in both sexes. During male puberty the MCRLH-RH decreased simultaneously to the stages of pubic hair development.