CS and neoplasm: This is in clear contrast to the tumour tissue with the A3243G mutation, which showed an upregulation of the mtDNA content (170%) and increased enzyme activities of complex II (138%), oligomycin-sensitive ATPase activity of complex V (1530%) and citrate synthase (575%) and a downregulation of the mitochondrial- and nuclear-encoded enzyme activities of complex I (22%) and complex IV (78%) related to the matching control tissue (Table 3).