Receptors for luteinizing hormone (LH) and follicle stimulating hormone (FSH) in the human undescended testis and the effect of hCG-treatment.

Human testis tissue contains specific receptors for luteinizing hormone (LH) and follicle stimulating hormone (FSH) with Ka's of 1.5 and 1.6 X 10(9) M-1, respectively. Specific binding of [125I]hLH and [125I]hFSH was studied in testicular biopsies from 33 boys (4-16 years of age) with undescended testes and in 2 adult men with normally descended testes. Ten of the boys were treated with human chorionic gonadotrophin (hCG) and operated 1-4 days after the last injection. Samples from each testis were taken for histological evaluation. Specific binding of LH in biopsies from pre-pubertal boys (stage I) was low and differentiated Leydig cells could not be identified histologically. In later pubertal stages the LH binding increased and differentiated Leydig cells could now be recognized. hCG-treatment caused a highly significant increase (P less than 0.001) in the binding of LH without affecting FSH binding. The highest binding of FSH occurred during the onset of puberty. Treatment with hCG did not cause premature differentiation of Sertoli cells or germ cells, but appeared to stimulate Leydig cells.