Involvement of thioredoxin in the regulation of growth hormone secretion in rat pituitary cell cultures

Ikue Hata, Yosuke Shigematsu, Yusei Ohshima, Hirokazu Tsukahara, Kazuo Fujisawa, Masahiro Hiraoka, Hajime Nakamura, Hiroshi Masutani, Junji Yodoi, Fumikazu Kotsuji, Masakatsu Sudo, Mitsufumi Mayumi

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We report here an examination of the effect of thioredoxin (TRX) on the secretion of growth hormone (GH) from rat anterior pituitary cells in vitro. Treatment of rat pituitary cells with growth hormone-releasing factor (GRF), but not GH, led to a significant increase in intracellular TRX protein levels. GRF, recombinant human TRX (rhTRX), and a combination thereof were all shown to induce immediate GH secretion from pituitary cells, as evidenced by perifusion experiments. RhTRX, but not other reducing agents such as β-mercaptoethanol and N-acetyl-L-cysteine, augmented GRF-stimulated and -unstimulated GH secretion from rat pituitary cells in a dose-dependent manner. RhTRX did not significantly affect the GH mRNA expression of pituitary cells stimulated in the presence or absence of GRF. In addition, rhTRX-augmented GH secretion was not significantly affected by the presence of cycloheximide. Collectively, these findings suggest that TRX is induced by stimulation with GRF and plays a regulatory role in GH secretion from rat anterior pituitary cells by enhancing the secretion of stored GH, rather than by the synthesis of GH.

Original languageEnglish
Pages (from-to)E269-E274
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume281
Issue number2 44-2
DOIs
Publication statusPublished - 2001

Keywords

  • Disulfide bonds
  • Growth hormone-releasing factor
  • Redox

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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    Hata, I., Shigematsu, Y., Ohshima, Y., Tsukahara, H., Fujisawa, K., Hiraoka, M., Nakamura, H., Masutani, H., Yodoi, J., Kotsuji, F., Sudo, M., & Mayumi, M. (2001). Involvement of thioredoxin in the regulation of growth hormone secretion in rat pituitary cell cultures. American Journal of Physiology - Endocrinology and Metabolism, 281(2 44-2), E269-E274. https://doi.org/10.1152/ajpendo.2001.281.2.e269