The formation of 25-hydroxycholecalciferol takes place in the-
Correct Answer: Liver
Description: In response to ultraviolet radiation of the skin, a photochemical cleavage results in the formation of vitamin D from 7-dehydrocholesterol. Vitamin D enters the circulation, whether absorbed from the intestine or synthesized cutaneously, bound to vitamin D-binding protein, an a-globulin synthesized in the liver. Vitamin D is subsequently 25-hydroxylated in the liver by cytochrome P450-like enzymes in the mitochondria and microsomes. 25-hydroxyvitamin D (25D), is the major circulating and storage form of vitamin D. The second hydroxylation, required for the formation of the mature hormone, occurs in the kidney. Reference : page 2463-64 Harrison's Principles of Internal Medicine 19th edition
Category:
Medicine
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now