Abbreviations used : DEX, dexamethasone ; ECL, enhanced chemiluminescence ; 5-HT, 5-hydroxytryptamine (serotonin) ; HPA, hypothalamic-pituitary-adrenal ; PDBu, phorbol 12, 13-dibutyrate ; PI, phosphatidylinositol ; PKC, protein kinase C ; TBST, 10 mM Tris base, 0.15 M NaCl, and 0.05% Tween 20.
Administration of Dexamethasone Up-Regulates Protein Kinase C Activity and the Expression of γ and ε Protein Kinase C Isozymes in the Rat Brain
Article first published online: 18 JAN 2002
Journal of Neurochemistry
Volume 72, Issue 1, pages 380–387, January 1999
How to Cite
Dwivedi, Y. and Pandey, G. N. (1999), Administration of Dexamethasone Up-Regulates Protein Kinase C Activity and the Expression of γ and ε Protein Kinase C Isozymes in the Rat Brain. Journal of Neurochemistry, 72: 380–387. doi: 10.1046/j.1471-4159.1999.0720380.x
- Issue published online: 18 JAN 2002
- Article first published online: 18 JAN 2002
- adrenal axis;
- Rat brain;
- Protein kinase C
Abstract : Altered hypothalamic-pituitary-adrenal (HPA) function (increased plasma cortisol level) has been shown to be associated with mood and behavior. Protein kinase C (PKC), an important component of the phosphatidyl-inositol signal transduction system, plays a major role in mediating various physiological functions. The present study investigates the effects of acute (single) and repeated (10-day) administrations of 0.5 or 1.0 mg/kg doses of dexamethasone (DEX), a synthetic glucocorticoid, on Bmax and KD of [3H]phorbol 12,13-dibutyrate ([3H]PDBu) binding, PKC activity, and protein expression of PKC isozymes, α, β, γ, δ, and ε in the membrane and the cytosolic fractions of rat cortex and hippocampus. It was observed that repeated administration of 1.0 mg/kg DEX for 10 days caused a significant increase in Bmax of [3H]PDBu binding to PKC, in PKC activity, and in expressed protein levels of the γ and ε isozymes in both the cytosolic and the membrane fractions of the cortex and the hippocampus, whereas a lower dose of DEX (0.5 mg/kg for 10 days) caused these changes only in the hippocampus. On the other hand, a single administration of DEX (0.5 or 1.0 mg/kg) had no significant effect on PKC in the cortex or in the hippocampus. These results suggest that alterations in HPA function from repeated administration of glucocorticoids may modulate PKC-mediated functions.