刊名:The Journal of Steroid Biochemistry and Molecular Biology
出版年:2017
出版时间:January 2017
年:2017
卷:165
期:part_PA
页码:101-108
全文大小:704 K
卷排序:165
文摘
Vitamin D is an inactive seco-steroid generated by opening the B-ring of 7-dehydrocholesterol in response to ultraviolet light. Activation of vitamin D to 1,25(OH)2D requires 25-hydroxylation and 1α-hydroxylation; inactivation is mainly via 24-hydroxylation. The three hydroxylations of vitamin D are catalyzed by cytochrome P450 enzymes: microsomal CYP2R1 and mitochondrial CYP27B1 and CYP24A1. Genetic disorders of CYP2R1 and CYP27B1 cause hypocalcemia and rickets; disorders of CYP24A1 cause neonatal hypercalcemia. Novel derivatives of vitamin D may be generated by cleavage of the cholesterol side chain via CYP11A1.