Beneficial effects of Ginkgo biloba extract on insulin signaling cascade, dyslipidemia, and body adiposity of diet-induced obese rats

Autor(es):Mostrar menos -

R.M. Banin ^[1] ; B.K.S. Hirata ^[1] ; I.S. Andrade ^[2] ; J.C.S. Zemdegs ^[2] ; A.P.G. Clemente ^[3] ; A.P.S. Dornellas ^[2] ; V.T. Boldarine ^[2] ; D. Estadella ^[4] ; K.T. Albuquerque ^[5] ; L.M. Oyama ^[2] ; E.B. Ribeiro ^[2] ; M.M. Telles ^[1]

Afiliação do(s) autor(es)

^[1] UNIFESP, Dept Ciencias Biol, BR-09972270 Diadema, SP - Brazil

^[2] Univ Fed Sao Paulo, Dept Fisiol, Disciplina Fisiol Nutr, Sao Paulo - Brazil

^[3] Univ Fed Alagoas, Fac Nutr, Maceio, AL - Brazil

^[4] Univ Fed Sao Paulo, Dept Biociencias, Baixada Santista, SP - Brazil

^[5] Univ Fed Rio de Janeiro, Curso Nutr, Macae, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 47, n. 9, p. 780-788, 2014-07-25.

Resumo

Ginkgo biloba extract (GbE) has been indicated as an efficient medicine for the treatment of diabetes mellitus type 2. It remains unclear if its effects are due to an improvement of the insulin signaling cascade, especially in obese subjects. The aim of the present study was to evaluate the effect of GbE on insulin tolerance, food intake, body adiposity, lipid profile, fasting insulin, and muscle levels of insulin receptor substrate 1 (IRS-1), protein tyrosine phosphatase 1B (PTP-1B), and protein kinase B (Akt), as well as Akt phosphorylation, in diet-induced obese rats. Rats were fed with a high-fat diet (HFD) or a normal fat diet (NFD) for 8 weeks. After that, the HFD group was divided into two groups: rats gavaged with a saline vehicle (HFD+V), and rats gavaged with 500 mg/kg of GbE diluted in the saline vehicle (HFD+Gb). NFD rats were gavaged with the saline vehicle only. At the end of the treatment, the rats were anesthetized, insulin was injected into the portal vein, and after 90s, the gastrocnemius muscle was removed. The quantification of IRS-1, Akt, and Akt phosphorylation was performed using Western blotting. Serum levels of fasting insulin and glucose, triacylglycerols and total cholesterol, and LDL and HDL fractions were measured. An insulin tolerance test was also performed. Ingestion of a hyperlipidic diet promoted loss of insulin sensitivity and also resulted in a significant increase in body adiposity, plasma triacylglycerol, and glucose levels. In addition, GbE treatment significantly reduced food intake and body adiposity while it protected against hyperglycemia and dyslipidemia in diet-induced obesity rats. It also enhanced insulin sensitivity in comparison to HFD+V rats, while it restored insulin-induced Akt phosphorylation, increased IRS-1, and reduced PTP-1B levels in gastrocnemius muscle. The present findings suggest that G. biloba might be efficient in preventing and treating obesity-induced insulin signaling impairment. (AU)

• Processo FAPESP: 11/06375-0 - Efeito do tratamento com Ginkgo biloba sobre a resistência à insulina em ratos com obesidade induzida pela dieta
• Beneficiário: Monica Marques Telles
• Modalidade de apoio: Auxílio à Pesquisa - Regular