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

Author(s)

Frasson, Danubia ^[1] ; Boschini, Renata Polessi ^[1] ; Chaves, Valeria Ernestania ^[1] ; Soares Martins dos Santos, Maria Emilia ^[1] ; Gomes, Silvia de Paula ^[1] ; Valentim, Rafael Rossi ^[1] ; Rissato Garofalo, Maria Antonieta ^[1] ; Carvalho Navegantes, Luiz Carlos ^[1] ; Migliorini, Renato Helios ^[1] ; Kettelhut, Isis do Carmo ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Physiol, BR-14049900 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: METABOLISM-CLINICAL AND EXPERIMENTAL; v. 61, n. 10, p. 1473-1485, OCT 2012.
• Web of Science Citations: 7

Abstract

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-{[}C-14]-pyruvate into glycerol-TAG. The denervation provokes a reduction (similar to 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 similar to 35% decrease in GyK activity of control rats and a further similar to 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. (C) 2012 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 06/00448-8 - Control of glycerol-3-phosphate generation and fatty acid esterification in liver and white and brown adipose tissues
• Grantee: Isis Do Carmo Kettelhut
• Support Opportunities: Regular Research Grants
• FAPESP's process: 10/12206-4 - Role of insulin and sympathetic nervous system in the control of glycerol-3-phosphate generation in white adipose tissue of rats
• Grantee: Isis Do Carmo Kettelhut
• Support Opportunities: Regular Research Grants