Calorie restriction increases insulin‐stimulated tyrosine phosphorylation of insulin receptor and insulin receptor substrate‐1 in rat skeletal muscle
Dean, Cartee - Acta physiologica scandinavica, 2000 - Wiley Online Library
Dean, Cartee
Acta physiologica scandinavica, 2000•Wiley Online LibraryA moderate reduction in calorie intake (calorie restriction, CR) improves insulin‐stimulated
glucose transport in skeletal muscle. Therefore, we studied muscle insulin signalling in ad
libitum (AL) and CR (~ 60% AL intake for 20 days) fed rats, which received a control injection
(sterile water) or an insulin injection (30 U kg–1 body weight). In control (not insulin‐treated)
rats, there was no detectable tyrosine phosphorylation of insulin receptor (IR), regardless of
diet; no diet effect on tyrosine phosphorylation of insulin receptor substrate‐1 (IRS1) or IRS1 …
glucose transport in skeletal muscle. Therefore, we studied muscle insulin signalling in ad
libitum (AL) and CR (~ 60% AL intake for 20 days) fed rats, which received a control injection
(sterile water) or an insulin injection (30 U kg–1 body weight). In control (not insulin‐treated)
rats, there was no detectable tyrosine phosphorylation of insulin receptor (IR), regardless of
diet; no diet effect on tyrosine phosphorylation of insulin receptor substrate‐1 (IRS1) or IRS1 …
A moderate reduction in calorie intake (calorie restriction, CR) improves insulin‐stimulated glucose transport in skeletal muscle. Therefore, we studied muscle insulin signalling in ad libitum (AL) and CR (~60% AL intake for 20 days) fed rats, which received a control injection (sterile water) or an insulin injection (30 U kg–1 body weight). In control (not insulin‐treated) rats, there was no detectable tyrosine phosphorylation of insulin receptor (IR), regardless of diet; no diet effect on tyrosine phosphorylation of insulin receptor substrate‐1 (IRS1) or IRS1‐associated phosphatidylinositol 3‐kinase (PI3K) protein and 21% higher IRS1‐associated PI3K activity in AL vs. CR. In insulin‐treated rats, tyrosine‐phosphorylated IR was 79% higher for CR vs. AL; tyrosine‐phosphorylated IRS1 was 109% higher for CR vs. AL; IRS1‐associated PI3K protein and IRS1‐associated PI3K activity were unaffected by diet. Calorie restriction amplifies early insulin signalling steps without changing IRS1‐associated PI3K, suggesting enhanced glucose transport is mediated by altering: IRS1‐PI3K localization, PI3K associated with proteins other than IRS1 or post‐PI3K events.
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