The alpha-subunit of glycoprotein hormones exists in the prolactin secretory granules of the bullforg (Rana catesbeiana) pituitary gland

Shigeyasu Tanaka, Fumihiko Mizutani, Kazutoshi Yamamoto, Sakaé Kikuyama, Kazumasa Kurosumi

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    Our recent finding that the number of immunoreactive α-subunit cells was invariably greater than the total number of immunoreactive gonadotropin (GTH) and thyrotropin (TSH) cells in the bullfrog (Rana catesbeiana) pituitary gland raises the possibility that the α-subunit also exists in pituitary cells other than GTH and TSH cells. The present study demonstrates that there are a considerable number of immunoreactive prolactin (PRL) cells that are also stained with antibody against the α-subunit when adjacent sections are immunocytochemically examined. Neither immunoreactive growth hormone nor adrenocorticotropin cells are stained with the antibody against the α-subunit. The specificity of the antibody against the α-subunit and of that against PRL was demonstrated by preabsorption test, non-competitive binding test, and immunoblot analysis. Double-immunolabeling with gold particles of different sizes for the α-subunit and PRL revealed that most of the immunolabeled PRL-secretory granules are also labeled with the α-subunit antibody. The gold particles indicating the presence of the α-subunit were mostly found in the peripheral zone of the secretory granules.

    Original languageEnglish
    Pages (from-to)223-231
    Number of pages9
    JournalCell and Tissue Research
    Issue number2
    Publication statusPublished - 1992 Feb



    • α-Subunit
    • Bullfrog, Rana catesbeiana (Anura)
    • Colocalization
    • Immunocytochemistry
    • Pars distalis
    • Pituitary glycoprotein hormone
    • PRL cell

    ASJC Scopus subject areas

    • Anatomy
    • Clinical Biochemistry
    • Cell Biology

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