Gene interactions and pathways from curated databases and text-mining
Diabetologia 2005, PMID: 16283248

Insulin signalling downstream of protein kinase B is potentiated by 5'AMP-activated protein kinase in rat hearts in vivo.

Longnus, S L; S├ęgalen, C; Giudicelli, J; Sajan, M P; Farese, R V; Van Obberghen, E

OBJECTIVE

5'AMP-activated protein kinase (AMPK) and insulin stimulate glucose transport in heart and muscle. AMPK acts in an additive manner with insulin to increase glucose uptake, thereby suggesting that AMPK activation may be a useful strategy for ameliorating glucose uptake, especially in cases of insulin resistance. In order to characterise interactions between the insulin- and AMPK-signalling pathways, we investigated the effects of AMPK activation on insulin signalling in the rat heart in vivo.

METHODS

Male rats (350-400 g) were injected with 1 g/kg 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) or 250 mg/kg metformin in order to activate AMPK. Rats were administered insulin 30 min later and after another 30 min their hearts were removed. The activities and phosphorylation levels of components of the insulin-signalling pathway were subsequently analysed in individual rat hearts.

RESULTS

AICAR and metformin administration activated AMPK and enhanced insulin signalling downstream of protein kinase B in rat hearts in vivo. Insulin-induced phosphorylation of glycogen synthase kinase 3 (GSK3) beta, p70 S6 kinase (p70S6K)(Thr389) and IRS1(Ser636/639) were significantly increased following AMPK activation. To the best of our knowledge, this is the first report of heightened insulin responses of GSK3beta and p70S6K following AMPK activation. In addition, we found that AMPK inhibits insulin stimulation of IRS1-associated phosphatidylinositol 3-kinase activity, and that AMPK activates atypical protein kinase C and extracellular signal-regulated kinase in the heart.

CONCLUSIONS

Our data are indicative of differential effects of AMPK on the activation of components in the cardiac insulin-signalling pathway. These intriguing observations are critical for characterisation of the crosstalk between AMPK and insulin signalling.

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Text Mining Data

insulin — AMPK: " In order to characterise interactions between the insulin- and AMPK signalling pathways, we investigated the effects of AMPK activation on insulin signalling in the rat heart in vivo "

glycogen synthase kinase 3 (GSK3) beta → Insulin: " Insulin induced phosphorylation of glycogen synthase kinase 3 (GSK3) beta , p70 S6 kinase (p70S6K) ( Thr389 ) and IRS1 ( Ser636/639 ) were significantly increased following AMPK activation "

p70 → Insulin: " Insulin induced phosphorylation of glycogen synthase kinase 3 (GSK3) beta, p70 S6 kinase (p70S6K) ( Thr389 ) and IRS1 ( Ser636/639 ) were significantly increased following AMPK activation "

IRS1 → Insulin: " Insulin induced phosphorylation of glycogen synthase kinase 3 (GSK3) beta, p70 S6 kinase (p70S6K) ( Thr389 ) and IRS1 ( Ser636/639 ) were significantly increased following AMPK activation "

insulin ⊣ AMPK: " In addition, we found that AMPK inhibits insulin stimulation of IRS1 associated phosphatidylinositol 3-kinase activity, and that AMPK activates atypical protein kinase C and extracellular signal regulated kinase in the heart "

Manually curated Databases

No curated data.