The sympathetic nervous system regulates the three glycerol-3P generation pathways in white adipose tissue of fasted, diabetic and high-protein diet-fed rats

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• 作者：Dan¨²bia Frasson ; Renata Polessi Boschini ; Val¨¦ria Ernestania Chaves ; Maria Em¨ªlia Soares Martins dos Santos ; S¨ªlvia de Paula Gomes ; Rafael Rossi Valentim ; Maria Antonieta Rissato Gar¨®falo ; Luiz Carlos Carvalho Navegantes ; Renato H¨¦lios Migliorini ; Isis do Carmo Kettelhut
• 关键词：WAT ; white adipose tissue ; TAG ; triacylglycerol ; FFA ; free fatty acid ; G3P ; glycerol-3-phosphate ; FA ; fatty acids ; GyK ; glycerokinase ; HP ; high protein ; carbohydrate-free diet ; PEPCK ; phosphoenolpyruvate carboxykinase ; SNS ; sympathetic nervous system ; N
• 刊名：Metabolism
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：61
• 期：10
• 页码：1473-1485
• 全文大小：696 K

文摘

The aim of the present study was to investigate the participation of the sympathetic nervous system (SNS) in the control of glycerol-3-P (G3P) generating pathways in white adipose tissue (WAT) of rats in three situations in which the plasma insulin levels are low. WAT from 48 h fasted animals, 3 day-streptozotocin diabetic animals and high-protein, carbohydrate-free (HP) diet-fed rats was surgical denervated and the G3P generation pathways were evaluated. Food deprivation, diabetes and the HP diet provoke a marked decrease in the rate of glucose uptake and glycerokinase (GyK) activity, but a significant increase in the glyceroneogenesis, estimated by the phosphoenolpyruvate carboxykinase (PEPCK) activity and the incorporation of 1-[¹⁴ C]-pyruvate into glycerol-TAG. The denervation provokes a reduction (~ 70 % ) in the NE content of WAT in fasted, diabetic and HP diet-fed rats. The denervation induced an increase in WAT glucose uptake of fed, fasted, diabetic and HP diet-fed rats (40 % , 60 % , 3.2 fold and 35 % , respectively). TAG-glycerol synthesis from pyruvate was reduced by denervation in adipocytes of fed (58 % ) and fasted (36 % ), saline-treated (58 % ) and diabetic (23 % ), and HP diet-fed rats (11 % ). In these same groups the denervation reduced the PEPCK mRNA expression (75 % -95 % ) and the PEPCK activity (35 % -60 % ). The denervation caused a ~ 35 % decrease in GyK activity of control rats and a further ~ 35 % reduction in the already low enzyme activity of fasted, diabetic and HP diet-fed rats. These data suggest that the SNS plays an important role in modulating G3P generating pathways in WAT, in situations where insulin levels are low.