IMMUNOHISTOCHEMICAL STUDY OF THE HUMAN PITUITARY WITH ANTI-LUTEINIZING HORMONE, ANTI-FOLLICLE STIMULATING HORMONE AND ANTI-THYROTROPHIN SERA

ABSTRACT Sections of fixed human pituitaries were investigated by an indirect immunofluorescence technique using antisera obtained following immunization of rabbits with human chorionic gonadotrophin (HCG), human hypophyseal gonadotrophins (HHG) and bovine hypophyseal thyrotrophin (BTSH) preparations. After microphotography of immunofluorescent positive cells, the tissue sections were stained by the Alcian blue (or Thionine aldehyde)-Periodic Acid Schiff-Orange G method. The microscopical fields which had been examined in immunofluorescence were then relocated and photographed again. A correlation was established between the cells reacting with an antiserum and the cell types of the morphological nomenclatures for human adenohypophysis proposed by Romeis (1940) and by Pearse & van Noorden (1963) and those of the functional classification proposed by Herlant & Pasteels (1967). The specificity of the antisera was checked by immunoelectrophoresis and by neutralization of the biological activities of luteinizing hormone (LH), follicle stimulating hormone (FSH) and BTSH. After selective absorption of the FSH neutralizing antibodies an anti-HCG serum became specific for LH. After selective absorption of the LH neutralizing antibodies an anti-HHG serum was found specific for FSH. The anti-BTSH sera neutralized the biological activity of human TSH, but cross reacted in immunoelectrophoresis with ovine LH and in immunofluorescence with the gonadotrophic cells of human pituitaries. After absorption with HCG, an anti-BTSH serum produced a specific immunofluorescence in large purple blue to dark blue Romeis δ cells filled with fine Alcian blue (or Thionine aldehyde) positive granules. This cell type is equivalent to the S2 mucoids of Pearse or to the "Thyrotrophs" of Herlant. The anti-LH and anti-FSH sera cross-reacted with TSH. Indeed, the S2 mucoids were also fluorescence positive with both anti-gonadotrophic sera. In addition, both anti-LH and anti-FSH sera produced a specific immunofluorescence in the group of purple coloured Romeis δ cells closely related to the S1 mucoids of Pearse. This would indicate that the same cell type contains immunoreactive LH and FSH, which is in contradiction with the description of two different gonadotrophic cell types based on histochemical stainings of human and animal pituitaries obtained in various physiopathological conditions.