Impaired lipolysis in fat-pads from mice homozygous for a deletion of the C/EBPβ gene (–/–). Periovarian fat-pads weighing 50–70 mg were isolated from fed C/EBPβ^–/– and WT control mice and incubated in 1 ml of Krebs-Henseleit buffer with 3% porcine albumin and 5 mM glucose at 37°C in a shaking water bath (30 cycles/min) for 3 h. The medium was gassed with 95% O₂/5% CO₂. Of the two fat-pads from each animal, one was incubated with epinephrine (5 μg/ml) and 0.01% ascorbic acid, while the other was incubated with a maximal dose of Bt₂cAMP (0.43 mg/ml) and theophylline (25 μg/ml). At the end of the 3-h incubation, the medium was frozen at –20°C for FFA and glycerol analysis as described in Methods. The DNA content was quantified in adipose tissue crude homogenates by a spectrofluorometric assay (31). The bars represent the mean ± SEM of 8–10 animals per group. *Significantly reduced compared with WT; P < 0.05. ⁺Significantly increased compared with epinephrine-treated; P < 0.05. FFA, free fatty acids