Differential regulation of glyceroneogenesis by glucocorticoids in epididymal and retroperitoneal white adipose tissue from rats

Author(s)

Ferreira, Graziella Nascimento ; Rossi-Valentim, Rafael ; Buzelle, Samyra Lopes ; Paula-Gomes, Silvia ; Zanon, Neusa Maria ; Rissato Garofalo, Maria Antonieta ; Frasson, Danubia ; Carvalho Navegantes, Luiz Carlos ; Chaves, Valeria Ernestania ; Kettelhut, Isis do Carmo

• Document type: Journal article
• Source: ENDOCRINE; v. 57, n. 2, p. 287-297, AUG 2017.
• Web of Science Citations: 2

Abstract

Purpose Investigate the glycerol-3-phosphate generation pathways in epididymal (EPI) and retroperitoneal (RETRO) adipose tissues from dexamethasone-treated rats. Methods Rats were treated with dexamethasone for 7 days. Glycerol-3-phosphate generation pathways via glycolysis, glyceroneogenesis and direct phosphorylation of glycerol were evaluated, respectively, by 2-deoxyglucose uptake, phosphoenolpyruvate carboxykinase (PEPCK-C) activity and pyruvate incorporation into triacylglycerol (TAG)-glycerol, and glycerokinase activity and glycerol incorporation into TAG-glycerol. Results Dexamethasone treatment markedly decreased the body weight, but increased the weight and lipid content of EPI and RETRO and plasma insulin, glucose, non-esterified fatty acid and TAG levels. EPI and RETRO from dexamethasone-treated rats showed increased rates of de novo fatty acid synthesis (80 and 100%) and basal lipolysis (20%). In EPI, dexamethasone decreased the 2-deoxyglucose uptake (50%), as well as glyceroneogenesis, evidenced by a decrease of PEPCK-C activity (39%) and TAG-glycerol synthesis from pyruvate (66%), but increased the glycerokinase activity (50%) and TAG-glycerol synthesis from glycerol (72%) in this tissue. In spite of a similar reduction in 2-deoxyglucose uptake in RETRO, dexamethasone treatment increased glyceroneogenesis, evidenced by PEPCK activity (96%), and TAG-glycerol synthesis from pyruvate (110%), accompanied by a decrease in glycerokinase activity (50%) and TAG-glycerol synthesis from glycerol (50%). Dexamethasone effects on RETRO were accompanied by a decrease in p-Akt content and by lower insulin effects on the rates of glycerol release in the presence of isoproterenol and on the rates of glucose uptake in isolated adipocytes. Conclusion Our data demonstrated differential regulation of glyceroneogenesis and direct phosphorylation of glycerol by glucocorticoids in EPI and RETRO from rats. (AU)

• FAPESP's process: 13/08553-9 - The role of the beta-arrestin signaling pathway in the control of cardiac muscle mass and cardiomyocytes culture of rodents
• Grantee: Sílvia de Paula Gomes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral