Therefore, in CKD there are three processes that lead to secondary hyperparathyroidism. 1) decreased renal mass leading to decreased production of 1,25(OH)2D leading to a compensatory rise in PTH to further enhance production of 1,25(OH)2D 2) inhibition of the renal 1-alpha-hydroxylase by accumulating phosphorus levels leading to decreased 1,25(OH)2D which also leads to secondary hyperparathyroidism. 3) increased phosphorus leads to lower ionized calcium leading to increased parathyroid hormone secretion.