Bone metabolism is primarily determined by the activity of the osteoblasts (cells which make bone) and osteoclasts (cells that resorb bone). These activities in turn are influenced by hormones like Vitamin D, parathyroid hormone and calcitonin.
Vitamin D are a group of structurally related hydrophobic vitamins of which the most important physiologically, are
Vitamin is converted into its active form by a two step hydroxylation process. First step takes place in liver where it is hydroxylated at 25th position to yield 25-OH vitamin D. The next hydroxylation takes place in the kidney at 1st position. This yields 1,25-dihydroxy vitamin D (the active form).
Most of the vitamin D (about 90 percent) is bound to vitamin D binding protein. Another 10 % is bound to albumin. Only about 1 percent of it is free. The free and albumin bound vitamin D are considered biologically active.
The individual product regulatory statements may vary, please refer to the instructions for use for more information.
|635||ELISA||25-OH vitamin D||antibody-coated
|25-OH vitamin D (D2 and D3)|
|636||ELISA||intact PTH|| antibody-coated
| recombinant human parathormone (1-84)
|synthetic human calcitonin|