Induction of adrenomedullin by hypoxia in cultured retinal pigment epithelial cells

T. Udono, K. Takahashi, M. Nakayama, A. Yoshinoya, Kazuhito Totsune, O. Murakami, Y. K. Durlu, M. Tamai, S. Shibahara

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51 Citations (Scopus)


Purpose. To explore the effects of hypoxia on the production and secretion of adrenomedullin (ADM) and endothelin (ET)-1 in human retinal pigment epithelial (RPE) cells. Methods. RPE cells were cultured under normoxic or hypoxic (1% O2) conditions. Expression of ADM and ET-1 was examined by Northern blot analysis and radioimmunoassay. Effects of ADM and ET-1 on the number of RPE cells were examined by modified 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results. ADM mRNA expression levels and immunoreactive ADM levels in the medium were increased by hypoxia in all three human RPE cell lines (ARPE-19, D407, and F-0202). Immunoreactive ET was detected in the cultured media of D407 cells and ARPE-19 cells and identified as ET-1 by reversed-phase high performance liquid chromatography. Hypoxia treatment for 48 hours increased immunoreactive ET levels approximately 1.3-fold in the cultured media of D407, but not ARPE-19 cells. Hypoxia decreased the number of ARPE-19 cells and F-0202 cells: and the treatment with ADM ameliorated the hypoxia-induced decrease in the cell number. In contrast, exogenously added ET-1 had no significant effects on the number of ARPE-19 cells under normoxia and hypoxia. Conclusions. Hypoxia increased the expression of ADM in all three human RPE cell lines, whereas the induction of ET-1 by hypoxia was found only in D407 cells. ADM induced by hypoxia may have protective roles against hypoxic cell damage in RPE cells.

Original languageEnglish
Pages (from-to)1080-1086
Number of pages7
JournalInvestigative Ophthalmology and Visual Science
Issue number5
Publication statusPublished - 2001 Apr 23

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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