Rapid suppressing action of insulin-like growth factor-I (IGF-I) on GH release from anterior pituitary cells of goats

K. Katoh, R. Shimoguchi, H. Ishiwata, Y. Obara

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)

    Abstract

    Goat anterior pituitary cells were cultured to investigate the effects of insulin-like growth factor-I (IGF-I), insulin, and growth hormone (GH) on basal and GH-releasing hormone (GHRH)-induced GH release. Changes in cellular Ca 2+ concentrations were also assessed to enable discussion of the cellular mechanisms of IGF-I. The cells were cultured for 48h, and then stimulated with GHRH (10nmol/l) for 30min, with or without each test substance. In the control cells, IGF-I (10 and 100ng/ml) significantly raised the basal, but did not change GHRH-induced GH release, resulting in the abolishment of GH release induced by GHRH in the presence of 100ng/ml IGF-I. However, there was no significant effect of insulin (10, 100, and 1000μU/ml) on basal and GHRH-induced GH release. In the cells cultured for 48h with each test substance but stimulated for 30min without the test substance, no significant change in the basal and GHRH-stimulated GH release was observed. Regardless of treatment, there was no significant effect on intra-cellular GH content. Analysis with a confocal laser microscope revealed that IGF-I (100ng/ml) significantly increased the basal, but significantly reduced GHRH (10nmol/l)-induced increase in cellular Ca2+ concentrations. From these findings we conclude that IGF-I exerts an acute suppressing action on the GHRH-induced GH release, which partly involves changes in cellular Ca2+ metabolism in goat somatotrophs.

    Original languageEnglish
    Pages (from-to)177-188
    Number of pages12
    JournalDomestic Animal Endocrinology
    Volume26
    Issue number3
    DOIs
    Publication statusPublished - 2004 Apr

    Keywords

    • Anterior pituitary cells
    • GH release
    • Goat
    • IGF-I

    ASJC Scopus subject areas

    • Food Animals
    • Animal Science and Zoology
    • Endocrinology

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