Induction of β₂-Adrenergic Receptor mRNA and Ligand Binding in HeLa Cells

Abstract

HeLa cells express low levels of β-adrenergic receptor (βAR) of the β₂-subtype. When exposed to sodium butyrate, receptor levels increased up to 4-fold in a time dependent manner, reaching a maximum after 12 to 15 h of treatment. Sodium butyrate treatment also caused a 3 to 4 fold increase in levels of β₂AR mRNA determined by hybridization blot analysis. The induction of β₂AR mRNA temporally preceded the increase in receptor binding activity, reaching a maximum after 4 to 6 h of treatment, and remaining elevated for up to 24 h. Prior exposure of the cells to the protein synthesis inhibitor cycloheximide prevented the butyrate-induced increase in receptor binding but had no effect on the increase in receptor mRNA. Blocking DNA synthesis and cell growth by excess thymidine did not increase β₂AR mRNA or binding or prevent the effects of sodium butyrate. Thus, butyrate appears to induce βAR mRNA by a mechanism independent of DNA and protein synthesis.