You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Active form of Vitamin D ? and explain in detail?
Ans. is 'c' i.e., CalcitriolVitamin D Vitamin D is the major vitamin involved in the absorption of calcium.Beside dietary intake, cutaneous synthesis is the other and more impoant source of vitamin D (cholecalciferol) in the body. The keratinocytes of stratum corneum of the epidermis of skin contain 7-dehydrocholesterol which is conveed to Vitamin D3 (cholecalciferol) by the action of sunlight (UV light).This vitamin D3 (Cholecalciferol) is conveed to calcidiol (calcifediol or 25 hydroxy cholecalciferol or 25-hydroxy vitamin D3) by 25 hydroxylase in the liver.Calcidiol is the major circulating form of vitamin D3.Calcidiol is then conveed to Calcitriol (1-25 dihydroxy-cholecalciferol or 1-25 dihydroxy vitamin D3) by 1-a hydroxylation in kidney.The final hydroxylation in kidney is rate limiting step.Calcitriol is the active form of vitamin D.Dietary vitamin D is absorbed in ileum and requires bile salts.When Ca2 level is high, little calcitriol is produced, and the kidney produce the relatively inactive metabolite 24, 25 dihydroxycholecalciferol instead.