figure 1 vitamin d synthesis figure vitamin d deficiency in ckd metabolic route of vitamin d nutrients 08 00291 g001 figure 1 risks of suboptimal vitamin d status in chronic kidney disease fibroblast growth factor 23 and disordered vitamin d metabolism in chronic kidney disease updating the trade off hypothesis american society of sources of vitamin d and its metabolism in the body interaction between vitamin d regulation and fibroblast growth factor 23 a new role for vitamin d receptor activation in chronic kidney disease renal physiology altered vitamin d metabolism in the course of kidney disease progression in chronic kidney disease figure background prevention and treatment of vitamin d insufficiency and vitamin d deficiency in ckd patients algorithm 1 vitamina d action full size image the vitamin d axis and the renin angiotensin aldosterone system raas in shining light on vitamin d trials in chronic kidney disease kidney international mitochondria activate vit d absorb more from gut high calcium negative feedback hyperparathyroidism 1ry extra secretion of pth 2ry kidney disease fig 23 3 effects of vitamin d full size image the vitamin d axis and the renin angiotensin aldosterone system raas in development of secondary hyperparathyroidism in patients with chronic kidney disease adapted from ronco et al vitamin d metabolism in chronic kidney disease findings and pathogenesis vitamin d therapy and cardiovascular morbidity and mortality in patients with chronic kidney disease cardiovascular diseases and vitamin d no various mechanisms relevant to vitamin d receptor in kidney diseases in various pathogenic conditions mcp 1 monocyte chemotactic protein 1 ctgf connective tissue growth factor rantes regulated on activation normal t cell expressed and mineral abnormalities of chronic kidney disease ckd no figure 1 effects of selective activation of vitamin d receptors in chronic kidney disease adapted from ronco et al 43 figure table 1 parison of means of vitamin d levels and percent of vitamin d deficiency in control subjects and in treated and untreated chronic kidney full size image fig 4 vitamin d deficiency and vitamin d metabolism and canine chronic kidney disease