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Induction of cellular responses and signaling pathways by bioassayable growth hormone
Author(s) -
Tracy Andrea C,
Ramos Yamil,
Herrera Gloria V,
Serrano Michelle N,
Cooper Rasalin D,
Gosselink Kristin L
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1010.7
Subject(s) - mapk/erk pathway , phosphorylation , signal transduction , cell growth , microbiology and biotechnology , growth factor , tyrosine phosphorylation , cell signaling , chemistry , in vitro , viability assay , chondrogenesis , biology , biochemistry , receptor
Bioassayable growth hormone (BGH) is an exercise‐responsive pituitary growth factor that stimulates bone growth through cartilage cell proliferation. In vivo testing for BGH activity requires large sample volumes and numerous experimental animals, limiting our ability to rapidly screen samples from experiments seeking to purify and characterize the BGH molecule. Therefore, our goal was to determine the viability of an in vitro bioassay for quantifying BGH activity and examining the cellular signaling pathways it utilizes. RCJ3.1C5.18 chondrogenic cells were grown to 10d post‐confluence, and stimulated under serum‐free conditions with whole or fractionated BGH‐containing samples. Proliferation was assessed by BrdU incorporation, and levels and activation of ERK and MEK signaling molecules evaluated by Western blot. Cellular proliferation correlated with the amount of BGH shown previously to be present in the samples, and BGH activity was highest in low molecular weight fractions (<10kD). These same fractions increased ERK expression and phosphorylation, and tyrosine phosphorylation, with few consistent effects on active or inactive MEK. The data demonstrate that BGH can stimulate cartilage cell division in vitro, through the induction of well‐known signaling cascades associated with growth factor receptor activation. Support: APS Frontiers, NIH 5G12 RR008124 , NIH 5R25 GM0490, HHMI 52005908