IMMUNOHISTOCHEMICAL LOCALIZATION OF GONADOTROPIN IN HUMAN TESTIS I

Abstract

Leydig cells of the testis have been repoted to be target cells of luteinizing hormone by biochemical studies. A limited number of histochemical studies have also shown the localization of the luteinizing hormone in the testicular tissue of experimental animals. However, there has been no report on the immunohistochemical localizations of gonadotropin in human testis.
The aim of the present study is to verify and discuss the localization of luteinizing hormone in the human testicular tissue using immunohistochemical technique. Anti-hCG antisera were obtained from the rabbit immunized by hCG (10, 000-15, 000iu/mg). Anti-rabbit IgG goat IgG were also received from the goat immunized by normal rabbit IgG, and, thereafter, they were labelled with fluorescein isothiocyanate (FITC) or horse radish peroxidase (HRP).
Immunohistochemical preparations were carried out as follows: (1) Testicular specimens were obtained from 20 cases of urological patients at the testicular operations. (2) Tissues were fixed immediately with cold 95% ethanol, 10% formalin or Zanboni solution.
Then, they were dehydrated, embedded in paraffin, and cut into 3-4μ sections. (3) Immunohistochemical stainings were performed using both indirect immunofluoresceine and immunoperoxidase techniques.
Immunohistochemical localizations of LH were clearly seen in the testicular interstitial cell of 16 cases except 3 cases of prostatic cancer after antiandrogen treatment and 1 case of 8 years old boy. Positive fluoresceine reactions were detected only in several Leydig cells, presumably immature Leydig cell, while reaction products were shown in the typical mature Leydig cell containing numbers of granules in the cytoplasm by the HRP method.
These localizations were limited only to cytoplasm of the interstitial cells. Reactions were not observed in the nucleus and cytoplasmic membrane by either FITC or HRP method. No reaction was found in the spermatogenic cells, Sertoli cells, basement membrane and peritubular myoid cells.
The present investigation demonstrated the immunohistochemical localization of LH in the interstitial cell cytoplasm of human testis. However, further study should be followed to clarify the intracellular site of gonadotropin by electron microscopic studies.