The focus of this study was to determine the potential biochemical mechanisms by which voluntary wheel running conferred beneficial effects observed in our previous study CKD-W as compared to CKD: (decreased creatinine 17%, phosphorous 16%, and parathyroid hormone 35%), increased time-to-fatigue 38% (during VO2max testing), reduced cortical porosity and improved bone microarchitecture as previously reported7. The gene discussed is PTH; the disease is chronic kidney disease.