Eutopic production of human chorionic gonadotropin β (hCGβ) and luteinizing hormone β (hLHβ) 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 bCGβ, hCGα 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 β ml in cubital vein serum versus up to 480 pg hCG β ml in the corresponding benign testicular hydrocele fluids. Moreover, hCGβ and its cognate molecule luteinizing hormone β (LHβ) were present in cytosolic extracts of normal human testes. Both hCGβ and hLHβ 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 hCGβ and hLHβ are synthesized in the human testis and autocrine/paracrine actions seem to be likely.