Neuroendocrine mediators up-regulate alpha(1b)- and alpha(1d)-adrenergic receptor subtypes in human monocytes

beta(2)- and alpha(2)-adrenergic receptors (AR) are thought to be the main AR subtypes to exert the effects of catecholamines on the immune system. Ho wever, in the present study, we demonstrate that another subtype of AR can be induced in human monocytes. Expression of alpha(1b)- and alpha(1d)-AR mR NA can be obtained by culturing freshly isolated human peripheral blood mon ocytes with the neuroendocrine mediators dexamethasone or the beta(2)-AR ag onist terbutaline. Using the human monocytic cell line THP-I, we demonstrat e that increased levels of alpha(1b)- and alpha(1d)-mRNA are accompanied by increased levels of receptor protein as determined by Western blot analysi s and radioligand binding assays. This study describes for the first time r egulated expression of alpha(1)-AR subtypes in human monocytes. (C) 1999 El sevier Science B.V. All rights reserved.