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Regulation of lipogenic enzyme and phosphoenolpyruvate carboxykinase gene expression in cultured white adipose tissue. Glucose and insulin effects are antagonized by cAMP
- Source :
- European Journal of Biochemistry. 223:893-900
- Publication Year :
- 1994
- Publisher :
- Wiley, 1994.
-
Abstract
- In cultured adipose tissue of suckling rats, glucose alone is able to induce the appearance of fatty-acid synthase and acetyl-CoA carboxylase mRNA by a mechanism involving glucose-6-phosphate accumulation; insulin alone has no effect but potentiates the effect of glucose. In the present study, we have analysed in cultured adipose tissue the effects of other hormones on the expression of these enzymes as well as on phosphoenolpyruvate carboxykinase. Triiodothyronine has only a marginal effect on fatty-acid synthase expression, in the absence or presence of glucose and insulin. A synthetic glucocorticoid, dexamethasone, opposes the inductive effect of glucose and insulin on fatty-acid synthase expression but increases the expression of phosphoenolpyruvate carboxykinase. A beta-agonist, isoproterenol totally inhibits the inductive effect of glucose and insulin on acetyl-CoA carboxylase and fatty-acid synthase expression whereas it increases the expression of phosphoenolpyruvate carboxykinase. Similarly, glucagon and cAMP have antagonistic effects on glucose and insulin-induced fatty-acid synthase expression. These inhibitory effects cannot be explained only by a reduction in glucose-6-phosphate concentration. We conclude that, in adipose tissue, dexamethasone and cAMP-generating hormones are negative regulators of lipogenic enzyme expression. Finally, the regulation of phosphoenolpyruvate carboxykinase expression in adipose tissue is similar to that found in the liver, i.e. inhibition by insulin and glucose and activation by glucocorticoids and cAMP.
- Subjects :
- Male
medicine.medical_specialty
medicine.medical_treatment
Adipose tissue
White adipose tissue
Biology
Biochemistry
Glucagon
Dexamethasone
Gene Expression Regulation, Enzymologic
Culture Techniques
Internal medicine
Gene expression
Cyclic AMP
medicine
Animals
Insulin
RNA, Messenger
Rats, Wistar
Isoproterenol
Animals, Suckling
Rats
Pyruvate carboxylase
Glucose
Endocrinology
Adipose Tissue
Triiodothyronine
Female
Phosphoenolpyruvate Carboxykinase (GTP)
Fatty Acid Synthases
Phosphoenolpyruvate carboxykinase
Glucocorticoid
Acetyl-CoA Carboxylase
medicine.drug
Subjects
Details
- ISSN :
- 14321033 and 00142956
- Volume :
- 223
- Database :
- OpenAIRE
- Journal :
- European Journal of Biochemistry
- Accession number :
- edsair.doi.dedup.....a45cb32242232dfb8a0ea68596f02fdc