Rat primary white adipocytes were incubated with isoprenaline (ISO; 200 nM) in the presence or absence of insulin (INS; 20 nM) for 4, 8, 12, 16 and 24 h. At the end of the incubation, culture medium was collected for the measurement of adiponectin (A) and leptin (B). *Indicates P<0.05 between indicated groups and untreated controls or the corresponding ISO+INS groups. † Indicates a statistical difference (P<0.05) between indicated groups and untreated controls only. Inserts: evaluation of intracellular adiponectin and leptin with Western blot analysis of whole cell extracts (see the Materials and methods section for details). Lane 1, untreated control; lane 2, ISO treated; lane 3, INS treated; lane 4, ISO+INS treated.