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Cortisol and IGF‐1 synergistically up‐regulate taurine transport by the rat skeletal muscle cell line, L6
Author(s) -
Park SungHee,
Lee Haemi,
Park Taesun
Publication year - 2004
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.552210179
Subject(s) - taurine , medicine , endocrinology , skeletal muscle , myocyte , transporter , hormone , chemistry , biology , biochemistry , amino acid , gene
This study was undertaken to evaluate effects of exercise‐induced hormones, cortisol, IGF‐1, and β‐endorphin, on the regulation of taurine transport activity in rat skeletal myoblasts, L6 cells. Challenge of L6 cells with cortisol (100 nM) for 24 hrs resulted in a 165% increase in taurine transport activity, 220% increase in V max of the taurine transporter, and 55% increase in taurine transporter/ β‐actin mRNA level compared with untreated control cells. Neither IGF‐1 (1∼100 nM) nor β‐endorphin (1∼20 nM), added in the incubation medium separately for 24 hrs, affected taurine uptake by L6 cells. However, when cells were co‐treated with IGF‐1 (10 nM) plus cortisol (100∼nM), taurine transport activity (37% increase, p < 0.05), V max of the transporter (54%, p < 0.05), and taurine transporter/ β‐actin mRNA level were further increased compared to the value for cells treated with cortisol alone. These results suggest that taurine transport by skeletal muscle cells appear to be synergistically up‐regulated during a prolonged exercise via elevated levels of cortisol and IGF‐1 in muscle.