Multiple mechanisms contribute to the regulation of G protein-coupled receptors and their transmembrane signaling. Post-translational modifications of the receptors, such as phosphorylation, and changes in receptor gene expression can occur in either a strictly agonist-dependent fashion or through second messenger-mediated autoregulation. We have shown that modulation of receptor gene expression contributes to the responsiveness of adrenergic and related receptors. Recent evidence for post-transcriptional regulation, as well as the stimulation of transcription in an autoregulatory manner, indicates the unanticipated variety and complexity of mechanisms regulating adrenergic receptor responsiveness.