The tissue distribution of the human β3-adrenoceptor studied using a monoclonal antibody:: Direct evidence of the β3-adrenoceptor in human adipose tissue, atrium and skeletal muscle

OBJECTIVE: To develop a monoclonal antibody that recognises an epitope of the native beta(3)-adrenoceptor expressed on the extracellular surface of human cells and tissues. DESIGN: A high affinity monoclonal antibody, Mab72c, was raised against the human beta(3)-adrenoceptor expressed on a transfected mammalian cell line. RESULTS: In CHO (Chinese hamster ovary) cells transfected with beta(3)-adrenoceptor cDNA, antibody labelling was found to be proportional to receptor density measured by the binding of the radiolabelled beta(3)-adrenoceptor antagonist, [I-125]iodocyanopindolol. The use of Mab 72c has demonstrated the expression of the beta(3)-adrenoceptor in a variety of human tissues, including gall bladder, prostate and colon, where a mRNA signal had been detected previously. This study also provides the first direct demonstration of the expression of beta(3)-adrenoceptors in human skeletal muscle, atrium and adipose tissue. CONCLUSION: The development of this antibody represents an important addition to the armentarium of reagents that are available to study the localisation of beta(3)-adrenoceptors in human tissues.