Endopeptidase-24.11 in the adenohypophysis of the pig is localized in the gonadotrophic cells.
Endopeptidase-24.11, an ectoenzyme with a key role in metabolizing peptides at cell surfaces, is present in the adenohypophysis. A specific polyclonal antibody to the endopeptidase has been used to explore its localization in cryostat sections of pig pituitary glands by an immunoperoxidase method. Immunoreactivity was symmetrically but not uniformly distributed over the anterior lobe, with the highest intensity a zone just beneath the capsule along the anterior surface. In detail, the staining was observed to be in the cell membrane, but in some cells a small area of intense paranuclear staining was also observed. Serial 5 micron sections were immunostained alternately for endopeptidase-24.11 and for pituitary proteohormone. Luteinizing hormone (LH), follicular stimulating hormone (FSH), thyrotropin, adrenocorticotropin, prolactin and growth hormone were studied in this way. It was possible to identify groups of cells in adjacent sections and a good correlation was observed for endopeptidase-24.11-immunoreactivity with that for LH and FSH. The association of the endopeptidase with gonadotrophs was confirmed by double labelling. No evidence of colocalization was observed with the other proteohormone antibodies. We conclude that among the cells of the adenohypophysis only the gonadotrophs express endopeptidase-24.11 and discuss the possible significance of this observation in regard to the termination of peptide signals, such as that of luteinizing hormone-releasing hormone (LHRH) acting at this site.
Barnes
K
K
Department of Biochemistry, University of Leeds, UK.
Kenny
A J
AJ
D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008666:Metalloendopeptidases / Q000032:analysis*; D015260:Neprilysin; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000201:enzymology*; D010907:Pituitary Hormones / Q000032:analysis; D013552:Swine
D010907:Pituitary Hormones; D008666:Metalloendopeptidases; D015260:Neprilysin