Sequential Sampling and Analysis of Renal Hydroxylase Activities of Cattle Given 1α-Hydroxyvitamin D3

Abstract
A new method was developed for sequential sampling of bovine renal cortex. This method results in minimum hemorrhage and adhesions and provides sufficient renal cortex tissue for assay of 25-hydroxyvitamin D 1.alpha., 24-, and 23-hydroxylase activities. Application of this procedure in calves and pregnant cows treated with 1.alpha.-hydroxyvitamin D3 is described. The success of these experiments suggests these techniques could be used to follow enzyme activities that control crucial aspects of vitamin D metbolism in normal peripartum cows and cows with milk fever or other diseases of mineral metabolism.