In which order do the following organs function in processing vitamin D3?

The correct sequence for processing vitamin D3 involves the liver first and then the kidneys. When vitamin D3 is produced in the skin through sunlight exposure or obtained from dietary sources, it is initially converted to calcidiol (25-hydroxyvitamin D) in the liver. This is the first step in the metabolism of vitamin D.

Following this liver conversion, calcidiol is then further processed into calcitriol (1,25-dihydroxyvitamin D) in the kidneys. Calcitriol is the active form of vitamin D, which plays a crucial role in calcium and phosphorus regulation in the body. Once synthesized in the kidneys, calcitriol is then ready to exert its biological effects on various organs.

Understanding this metabolic pathway emphasizes the importance of both the liver and kidneys in converting vitamin D3 into its active form, with the liver initiating the process and the kidneys finalizing it, leading to the desired "Result" of increased calcium absorption and bone health.