Heat stress acutely activates insulin-independent glucose transport and 5'-AMP-activated protein kinase prior to an increase in HSP72 protein in rat skeletal muscle.

Heat stress (HS) stimulates heat shock protein (HSP) 72 mRNA expression, and the period after an increase in HSP72 protein is characterized by enhanced glucose metabolism in skeletal muscle. We have hypothesized that, prior to an increase in the level of HSP72 protein, HS activates glucose metabolism by acutely stimulating 5'-AMP-activated protein kinase (AMPK). Rat epitrochlearis muscle was isolated and incubated either with or without HS (42°C) for 10 and 30 min.

Evidence for organic cation transporter-mediated metformin transport and 5'-adenosine monophosphate-activated protein kinase activation in rat skeletal muscles.

Objective: 5'-Adenosine monophosphate-activated protein kinase (AMPK) is a key molecule of metabolic enhancement in skeletal muscle. We investigated whether metformin (MET) acts directly on skeletal muscle, is transported into skeletal muscle via organic cation transporters (OCTs), and activates AMPK.

Materials/methods: Isolated rat epitrochlearis and soleus muscles were incubated in vitro either in the absence or in the presence of MET.

Salicylate acutely stimulates 5'-AMP-activated protein kinase and insulin-independent glucose transport in rat skeletal muscles.

Salicylate (SAL) has been recently implicated in the antidiabetic effect in humans. We assessed whether 5'-AMP-activated protein kinase (AMPK) in skeletal muscle is involved in the effect of SAL on glucose homeostasis. Rat fast-twitch epitrochlearis and slow-twitch soleus muscles were incubated in buffer containing SAL.