FIGURE 4.

Superoxide production of brown adipose tissue mitochondria from cold-acclimated wild type (UCP1^+/+) and UCP1-ablated (UCP1^−/−) mice mitochondria by complex I (pyruvate/malate). A mixture of pyruvate (5 mm) and malate (3 mm) was used to provide complex I with NADH. By supplemental addition of rotenone (Rot), we showed that UCP1 provides superoxide production by reverse electron transfer. Independent experiments were performed with wild type mitochondria (n = 4) and UCP1-ablated mice mitochondria (n = 8) (#, p < 0.05 Mann Whitney U test).