Protein kinase Cμ mediates adenosine-stimulated steroidogenesis in primary rat adrenal cells

FEBS Lett. 2010 Nov 5;584(21):4442-8. doi: 10.1016/j.febslet.2010.10.001. Epub 2010 Oct 13.


Adenosine (Ado), an endogenous nucleoside, can stimulate corticosterone synthesis in adrenal cells via the A(2A)/A(2B) adenosine receptors (ARs). This study evaluated the contribution of protein kinase C (PKC) isoforms in Ado-induced steroidogenesis. The PKC inhibitor calphostin c blocked Ado-induced steroidogenesis, the mitogen-activated protein kinase (MEK)-extracellular signal-related regulated kinase (ERK)-cyclic AMP responsive element-binding protein cascade, and the mRNA expression of steroidogenic acute regulatory protein and CYP11B1. Further analyses revealed that PKCμ was indeed activated by Ado. Moreover, downregulation of PKCμ by small interfering RNA (siRNA) inhibited Ado-stimulated steroidogenesis and ERK phosphorylation. Finally, inhibition of either A(2A)AR or A(2B)AR led to the suppression of PKCμ phosphorylation. Together, these findings suggest that A(2)AR-PKCμ-MEK signaling mediates Ado-stimulated adrenal steroidogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / pharmacology*
  • Adrenal Glands / cytology*
  • Adrenal Glands / drug effects
  • Adrenal Glands / metabolism
  • Animals
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Gene Expression Regulation / drug effects
  • MAP Kinase Signaling System / drug effects
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Phosphoproteins / genetics
  • Phosphorylation / drug effects
  • Protein Kinase C / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Receptor, Adenosine A2B / metabolism
  • Steroids / biosynthesis*


  • Cyclic AMP Response Element-Binding Protein
  • Phosphoproteins
  • RNA, Messenger
  • Receptor, Adenosine A2B
  • Steroids
  • steroidogenic acute regulatory protein
  • protein kinase D
  • Protein Kinase C
  • Extracellular Signal-Regulated MAP Kinases
  • Mitogen-Activated Protein Kinase Kinases
  • Adenosine