A HIGHLY SENSITIVE IN VITRO BIOASSAY FOR LUTEINIZING HORMONE AND CHORIONIC GONADOTROPIN: TESTOSTERONE PRODUCTION BY DISPERSED LEYDIG CELLS.

Abstract

The in vitro bioassay for LH/hCG employing isolated rat testes has been significantly improved by utilization of collagenase-dispersed interstitial cells in the presence of phosphodiesterase inhibitors. The sensitivity of the assay system has been extended to 20μIU (2 picograms) of hCG, and the index of precision of the method (λ) is less than 0.04. The high sensitivity of the interstitial cell assay permits bioassay of circulating gonadotropins in human plasma.