Effect of resistin on mitochondrial biogenesis in placentae. Human placental explants were treated with indicated doses of human resistin for 24 h. a protein lysates were subjected for Western blot analysis; b total DNA were extracted and mitochondrial DNA copy number was determined by fold change of mitochondrial tRNALeu(UUR) gene DNA copy number normalized to nuclear β2 microglobin (B2M) with quantitative RT-PCR. Mean ± SD, ** P < 0.01; *** P < 0.001; N = 4. # P < 0.05 with one-tail T-test