NUTR 3210 Lecture Notes - Lecture 20: Calcifediol, Hypervitaminosis A, Calcitriol
24 Nov 2016
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Document Summary
1, 25, vitamin d form in made through a second reaction, in the kidney. This is the bioactive form: 25 oh vitamin d (calcidiol) (liver, d3 (cholecociferol, d2 (ergocalciferol, 1, 25, dioh vitamin d (calcitriol) Vitamin d synthesis: 10-15 minutes of noon time sun exposure to make 10,000 iu of dietary d3, uv rays and infrared heat, start with 7-dehydrycholesterol, which is converted to the precursor vitamin. This is the circulating form, not active: in the kidney, 1 hydroxylase converts calcidiol into calcitriol (inserts oh to carbon 1). Now in its active form. , frunctions as a hormone. Short lived, and targets bone, intestinal enterocytes, and kidneys. Calcidiol: 25 oh vitamin d, formed by hydroxylation of d3 in the liver, inactive, but primary circulating form, half life of 15 days (this is a long halflife, considered to be a homeostatic set point.
