Moreover, repletion of 25(OH)D3 in CKD mice significantly decreased expression of pro-fibrotic genes (PAI-1, IL-1α, IL-1β, Agt, Ctgf, Akt1 and Smad3) and increased the expression of anti-fibrotic genes (Bmp7 and IL-13Rα2) the repletion of 1,25(OH)2D3. The gene discussed is SMAD3; the disease is chronic kidney disease.