1-a hydroxylation in Vitamin-D metabolism takes place in

Vitamin D is a fat-soluble vitamin molecule found in fish liver oils, and also produced in the skin when subjected to ultraviolet rays from sunlight. The main function of the vitamin is to increase the utilization of calcium and phosphorus in bones and teeth. A mixture of several forms of vitamin D: Vitamin D3 is synthesized in the skin upon exposure to ultraviolet light; in contrast, vitamin D2 is obtained only from the diet. Both vitamins D2 and D3 are metabolized to 25-hydroxyvitamin D in the liver, and then to the active 1,25 dihydroxy form in the kidney. Vitamin D has a major role in the intestinal absorption of calcium, bone calcium balance and renal excretion of calcium.Ref: Ganong&;s review of medical physiology;24th edition; page no-379