Citrate synthase activity, a ubiquitous marker for mitochondrial content,[27] was significantly reduced in the CKD rats, pointing to reduced number of intact mitochondria in this model (1.83±0.03x10-3 nmole/min/μl in CKD versus 2.15±0.03x10-3nmole/min/μl in sham animals, p<0.0001). This evidence concerns the gene CS and chronic kidney disease.