Eutopic production of human chorionic gonadotropin beta (hCG beta) and luteinizing hormone beta (hLH beta) in the human testis

Abstract

The classical pregnancy and tumor marker hCG has long been considered to be only accidentally expressed ectopically, e.g. by tumors. The biological functions of low levels of hCG beta, hCG alpha and holo-hCG in the sera of nonpregnant healthy individuals remained unclear. Immunological analyses by our ultrasensitive time-resolved fluoroimmunoassays revealed a concentration gradient from < 5 pg hCG beta/ml in cubital vein serum versus up to 480 pg hCG beta/ml in the corresponding benign testicular hydrocele fluids. Moreover, hCG beta and its cognate molecule luteinizing hormone beta (LH beta) were present in cytosolic extracts of normal human testes. Both hCG beta and hLH beta are eutopically produced as proven by RT-PCR and subsequent Southern and dot blot analyses. Thus, the view of a purely systemic hormonal function of hLH, and of hCG during pregnancy needs a reassessement as hCG beta and hLH beta are synthesized in the human testis and autocrine/paracrine actions seem to be likely.