HUMAN IMMORTALIZED BROWN ADIPOCYTES EXPRESS FUNCTIONAL BETA(3)-ADRENOCEPTOR COUPLED TO LIPOLYSIS

Human brown pre-adipocytes were immortalized by microinjection of the genes encoding simian virus 40 T and t antigens under the control of t he human vimentin promotor, The transfected pre-adipocytes were cultur ed for several months with no loss of their morphological characterist ics, These cells accumulate lipids and differentiate into adipocytes w hen treated with insulin, triiodothyronine and dexamethazone. The mRNA of various adipocyte markers was detected by reverse transcriptase-po lymerase chain reaction analysis, including hormone-sensitive lipase, lipoprotein lipase, adipsin, glucose transporters 1 and 4, the uncoupl ing protein (specific of brown adipocytes), and leptin, the product of the ob gene, Pharmacological analyses indicated that the beta(3)-adre noceptor is the predominant beta-adrenoceptor subtype in PAZ6 cells an d that this receptor subtype is functionally coupled to adenylate cycl ase and lipolysis, The immortalization of human adipocytes will permit pharmacological analysis of the human beta(3)-adrenoceptor function i n adipose cells and will allow detailed studies of human adipocyte dif ferentiation.