Agonist regulation of gene expression of adrenergic receptors and G proteins.

Study of transmembrane signaling via G proteins has focused to a large extent upon investigations of individual G protein-linked receptor-effector systems. Agonist-induced desensitization and down-regulation of beta-adrenergic receptors, for example, have been studied extensively and adopted as a general model for G protein-linked receptor regulation. This review focuses not only on agonist regulation of adrenergic receptor gene expression, but also on how agonists regulate opposing adrenergic receptor-mediated pathways. This important feature of G protein-mediated pathways, i.e., cross-regulation and integration of information among several pathways, will be discussed in the context of what has been learned in the adrenergic receptor-coupled pathways.