Estrogen receptors in the stingray (Dasyatis akajei) ultimobranchial gland

Kazutoshi Yamamoto, Nobuo Suzuki, Noriyuki Takahashi, Yuichi Sasayama, Sakae Kikuyama

    Research output: Contribution to journalArticle

    13 Citations (Scopus)

    Abstract

    On the basis of our previous observation that estrogen stimulates calcitonin secretion by the ultimobranchial gland in the stingray, Dasyatis akajei, experiments were conducted to examine the presence of estrogen receptor (ER) and its mRNA in the gland, employing exchange assay and Northern blot analysis, respectively. The optimal incubation conditions of the exchange assay for cytosolic ER were found to be 25° for 2 hr. Scatchard analysis of cytosolic ER revealed two components with dissociation constants (K(d)) of 0.090 ± 0.015 and 17.780 ± 1.910 nM and with a maximum number of binding sites (B(max)) of 62.2 ± 7.9 and 2290 ± 180 fmol/mg protein, respectively. Furthermore, Sephadex G-100 filtration of the cytosol and immunoblot analysis using antiserum against a recombinant rat ER confirmed the presence of two specific binding components for estrogen (41 and 57 kDa). Total RNA extracted from the ultimobranchial gland was subjected to Northern blot analysis using a rat ER cDNA as a probe. Two positive signals were detected at 2.5 and 2.0 kb. Thus, the presence of ER was confirmed for the first time in nonmammalian calcitonin-secreting cells.

    Original languageEnglish
    Pages (from-to)107-114
    Number of pages8
    JournalGeneral and Comparative Endocrinology
    Volume101
    Issue number1
    DOIs
    Publication statusPublished - 1996 Jan

    ASJC Scopus subject areas

    • Endocrinology

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