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Transforming growth factor‐β1 rapidly activates phosphorylase in a calcium‐dependent manner in rat hepatocytes
Author(s) -
Hahm Sung Ho,
Cooper Ronald H.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81361-o
Subject(s) - glycogen phosphorylase , transforming growth factor , chemistry , calcium , signal transduction , microbiology and biotechnology , biophysics , endocrinology , biochemistry , medicine , biology , enzyme , organic chemistry
Transforming growth factor‐β1 (TGF‐β1) rapidly activated phosphorylase in isolated rat hepatocytes (half‐maximal rate of activation with approximately 0.1 ng/ml). Removal of Ca 2+ from the external medium just before TGF‐β1 addition markedly attenuated phosphorylase activation. TGF‐β1 (1 ng/ml) produced a small increase in [Ca 2+ ] i (approximately 10% increase after 30 s), which appears sufficient to account for phosphorylase activation. These observations indicate that activation of the TGF‐β1 signal transduction system in hepatocytes is linked with a small increase in [Ca 2+ ] i , and external Ca 2+ may contribute in part to this increase.