Dose-specific or dose-dependent effect of growth hormone treatment on the proliferation and differentiation of cultured neuronal cells

Esther Lyuh, Hyun Jung Kim, Manho Kim, Jung Kwon Lee, Kyong Soo Park, Keun-Young Yoo, Kwang Woo Lee, Yoon Ok Ahn

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Objective: GH controls the proliferation of cartilage, fibroblasts or the differentiation of adipose and muscle tissue. However, the effect of GH on neuronal cells remains unknown. The present study was conducted to determine the proliferative or differentiating effect of GH on the nervous system in vitro. Design: Neuronal hybrid cells (VSC4.1) were cultured with GH. The concentration ranged from 0.134 μg/ml up to 1.34 mg/ml. A cell confluency and MTT assay, cell cycle phase analysis with flow cytometry, extracellular receptor kinase (ERK) phosphorylation and mitogen activated protein kinase (MAPK) inhibitor (PD98050) assays were all performed to determine the effect on proliferation. Differentiation was evaluated by neurite outgrowth and neurofilament expression. Terminally differentiated neurons were stained by Hoechst 33342 for apoptotic nuclear fragmentation by degeneration. Poly-adenosyl ribose polymerase (PARP) expression and its cleavage products were evaluated. Results: Cells at concentrations between 0.134 μg/ml and 1.34 μg/ml of GH proliferated with ERK phosphorylation, which was attenuated by MAPK inhibitors. Proliferation decreased at concentrations higher than 13.4 μg/ml; however, neurite outgrowth was observed at these concentrations. Terminally differentiated cells underwent apoptosis and showed nuclear fragmentation by Hoechst 33342 staining. PARP expression was increased with caspase-3 dependent-cleaved fragment. Conclusions: Our in vitro data demonstrate that GH exerts dual effects; proliferation with a specific GH dose window, or differentiation in a dose-dependent manner in cultured neuronal hybrid cells.

Original languageEnglish
Pages (from-to)315-322
Number of pages8
JournalGrowth Hormone and IGF Research
Volume17
Issue number4
DOIs
StatePublished - Aug 2007

Keywords

  • Differentiation
  • Extracellular receptor kinase (ERK)
  • Growth hormone
  • Neuronal cells
  • Proliferation

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