Which of the following feedback mechanisms regulate the production of 1, 25(OH)₂D₃? A) Negative feedback mechanism associated with circulating levels of calcium and inorganic phosphorus B) Negative feedback mechanism associated with circulating levels of calcitonin C) Negative feedback mechanism associated with circulating levels of magnesium D) Positive feedback mechanism associated with circulating levels of calcium and inorganic phosphorus

Question

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The production of 1,25-dihydroxyvitamin D (1,25(OH)₂D), also known as calcitriol, is regulated by a negative feedback mechanism associated with circulating levels of calcium and inorganic phosphorus. When calcium or phosphorus levels are low, parathyroid hormone (PTH) levels increase, stimulating the conversion of 25-hydroxyvitamin D into 1,25(OH)₂D in the kidneys, which helps to increase calcium and phosphorus levels in the blood. Conversely, when calcium and phosphorus levels are high, the production of 1,25(OH)₂D is decreased.

Which of the Following Feedback Mechanisms Regulate the Production of 1