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Modulation of Insulin Signaling via Resistance Exercise
Author(s) -
Hamilton David Lee,
Mackenzie Matthew Graeme,
Baar Keith Richard
Publication year - 2008
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.22.1_supplement.959.21
Subject(s) - p70 s6 kinase 1 , phosphorylation , endocrinology , stimulation , medicine , insulin resistance , kinase , serine , insulin , chemistry , protein kinase b , biochemistry
Resistance exercise in rats has been shown to substantially elevate S6K1 phosphorylation for up to 36 hr post exercise. Genetically increasing the activity of S6K1 can alter insulin sensitivity by inhibition of IRS‐1 expression and function. We hypothesized that lengthening contractions would increase S6K1 phosphorylation and down regulate the expression and function of IRS‐1. Wistar rats underwent unilateral lengthening contractions of the right Tibialis Anterior muscles and were collected at 0 mins, 30 mins, 3 hrs, 18 hrs and 48 hrs. S6K1 389 phosphorylation was elevated by 751 ± 208 %, 3197 ± 1144 %, 10041 ± 2209 % (p < 0.05), at 0 min, 30 min, 3 hr, respectively. IRS‐1 636/639 phosphorylation was significantly increased at 30 mins and 18 hrs by 715 ± 160 % and 170 ± 38 %, respectively. IRS‐1 associated P85 was significantly reduced at 30 min and 3 hrs by 57 ± 7 % and 55 ± 7 %, respectively. Due to the time course of the S6K1 389 and IRS‐1 636/639 phosphorylation we concluded that S6K1 was the most likely kinase mediating the response. To test this further we pretreated female Wistar rats with rapamycin and collected tissues 30 mins post stimulation. We found that rapamycin reduced the increase in IRS‐1 636/639 phosphorylation and partially rescued the reduction in IRS‐1 associated P85. We conclude that increased S6K1 activity after resistance exercise enhances IRS‐1 serine phosphorylation, decreasing IRS‐1 associated P85.