CYP24A1 and type 2 diabetes mellitus: (11) Type 2 diabetes patients also have low serum 25(OH)D3 levels,(12) while woman with metabolic syndrome have high serum 25(OH)D levels.(13) In the db/db mouse model of type 2 diabetes, up-regulation of renal Cyp24a1 expression is associated with decreased vitamin D levels.(14) Moreover, Vuica et al.(15) showed a significant increase in Cyp24a1 expression in hepatocytes from long-term type 1 diabetes rats induced by streptozotocin (STZ), which can injure pancreatic β cells.