we separately measured 25-hydroxyvitamin d3 ( 25ohd3 ) , 25ohd2 , 1,25- ( oh ) 2d3 , and 1,25- ( oh ) 2d2 to assess contributions to total 1.25- ( oh ) 2d from endogenous biosynthesis ( 1 alpha-hydroxylation of 25ohd2 or 25ohd3 ) vs. contributions from exogenously administered 1.25- ( oh ) 2d3 .
C0006657
25-hydroxyvitamin
C2713074
25ohd3