EFFECTS OF ENDURANCE TRAINING ON GENE-EXPRESSION OF INSULIN SIGNAL-TRANSDUCTION PATHWAY

Alternative splicing of insulin receptor mRNA and gene expression of i nsulin receptor, IRS-1 and MAP kinase isoforms were examined in skelet al muscle of trained and sedentary rats. Adult male Sprague-Dawley rat s were trained for 9 weeks on a treadmill : 30 m/min at 6 degrees incl ine, 90 min/day, 5 days/week. Endurance training increased insulin rec eptor mRNA level without change in alternative splicing of insulin rec eptor mRNA in skeletal muscle. The levels of IRS-1 and MAP kinase (ERK I) mRNA were significantly higher in trained rats than sedentary rats. Our findings provide the first evidence that gene expression of insul in receptor and postreceptor signal transduction pathway is enhanced b y endurance training, without affecting alternative splicing of insuli n receptor isoforms. (C) 1995 Academic Press, Inc.