Background: Obesity and type 2 diabetes (T2D) are associated with elevated plasma free fatty acids (FFA). In vivo exposure to FFAs, such as palmitate, by lipid infusion results in insulin resistance as observed in obesity and T2D. In recent years, compounds found in herbs and plants have attracted attention for prevention and treatment of insulin resistance and T2D. In recent studies by our group, carnosic acid (CA), found in rosemary, increased glucose uptake and attenuated the FFA (palmitate)-induced insulin resistance in muscle cells and adipocytes. In addition, CA caused a robust activation of AMP-activated protein kinase (AMPK). Our present study aimed to examine the effects of CA in short-term FFA-induced glucose intolerance in mice.

Material and Methods: C57Bl/6J mice were cannulated in their jugular veins and infused for 48h with ethylpalmitate (EtP, nontoxic method of elevating circulating palmitate because of hydrolysis to palmitate and ethanol by plasma esterases), mimicking elevated FFA levels seen in obesity. In addition, a group of mice were infused with EtP plus 50 mg/kg CA for 48h. Ethanol vehicle with or without CA were two additional control groups. At the end of the infusions, the mice were subjected to a 2 hr hyperglycemic clamp (20 mM glucose) and the glucose infusion rate was measured to assess glucose tolerance.

Results: Preliminary data revealed that mice infused with EtP and CA had a higher glucose infusion rate (GIR; mg/kg*min) (66.5±10, mean±SEM) than mice infused with EtP alone (22.7±10). The EtP and CA was comparable to the GIR of ethanol vehicle infused mice (73±9).

Future Directions: Further analysis of collected plasma and tissue will be used to assess insulin resistance and beta cell function in vivo and to elucidate the mechanisms of CA alleviation of FFA-induced insulin resistance.

Conclusions: Our data indicate that CA has the potential to counteract FFA-induced glucose intolerance in mice.


N.Tsakiridis: None. F.Vlavcheski: None. E.Tsiani: None. A.Giacca: None.

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