The regulation of plasma calcium concentration is primarily controlled by parathyroid hormone (PTH) and calcitriol, with calcitonin having minimal influence in humans. PTH, plasma calcium concentration, and calcitriol play a role in regulating calcium excretion by the kidneys, which can be affected by changes in acid-base status, extracellular fluid volume (ECFV), and plasma phosphate levels.

The reabsorption of calcium by the thick ascending limb (TAL) and distal tubule is stimulated by PTH and calcitriol, as well as by the concentration of plasma calcium.

The regulation of plasma phosphate concentration involves PTH, fibroblast growth factor-23 (FGF-23), and calcitriol. Phosphate excretion is regulated by PTH, FGF-23, dietary phosphate, and growth hormone, and can be influenced by acid-base balance, expansion of ECFV, and glucocorticoids. FGF-23 secreted by bone tumors can lead to increased renal phosphate excretion, resulting in hypophosphatemia, hyperphosphatemia, and impaired bone mineralization (osteomalacia).

References:
1. Biber J, et al. Phosphate transporters and their function. Annu Rev Physiol. 2013;75:535-550.
2. Christov M, Juppner H. Insights from genetic disorders of phosphate homeostasis. Semin Nephrol. 2013;33:143-157.
3. Miller T. Control of renal calcium, phosphate, electrolyte, and water excretion by the calcium-sensing receptor. Best Pract Res Clin Endocrinol Metab. 2013;27:345-358.
4. Palmer BF. Regulation of potassium homeostasis. Clin J Am Soc Nephrol. 2015;10:1050-1060.
5. Patel A. The primary cilium calcium channels and their role in flow sensing. Pflugers Arch. 2015;467:157-165.
6. Pearce D, et al. Collecting duct principal cell transport processes and their regulation. Clin J Am Soc Nephrol. 2015;10:135-146.
7. Bernardo JF, Friedman PA. Renal calcium metabolism. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2225.
8. Berndt TJ, Kumar R. Clinical disturbances of phosphate homeostasis. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2369.
9. Malnic G, et al. Regulation of K+ excretion. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:1659.
10. Murer H, et al. Proximal tubular handling of phosphate. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2351.
11. Smogorzewski MJ, et al. Disorders of calcium, magnesium, and phosphate balance. In: Taal MW, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia: Saunders; 2012:689.
Plasma [Ca++] is regulated by PTH and calcitriol. Calcitonin is not a major regulatory hormone in humans. Ca++ excretion by the kidneys is regulated by PTH, plasma [Ca++], and calcitriol and is altered by changes in acid-base status, ECFV, and plasma Pi.
5.
Ca++ reabsorption by the TAL and distal tubule are regulated by PTH and calcitriol, both of which stimulate Ca++ reabsorption, and by plasma [Ca++].
6.
Plasma [Pi] is regulated by PTH, FGF-23, and calcitriol. Pi excretion is regulated by PTH, FGF-23, dietary phosphate, and growth hormone and is  altered by acid base balance, ECFV expansion,  and glucocorticoids. Bone tumors secrete FGF-23, which enhances renal Pi excretion and thereby causes hypophosphatemia, hyperphosphatemia,  and a defect in bone mineralization (i.e.,  osteomalacia).
Biber J, et al. Phosphate transporters and their function. Annu Rev Physiol. 2013;75:535-550. Christov M, Juppner H. Insights from genetic disorders of phosphate homeostasis. Semin Nephrol. 2013;33:143-157.
Miller T. Control of renal calcium, phosphate, electrolyte, and water excretion by the calcium-sensing receptor. Best Pract Res Clin Endocrinol Metab. 2013;27:345-358.
Palmer BF. Regulation of potassium homeostasis. Clin J Am Soc Nephrol. 2015;10:1050-1060.
Patel A. The primary cilium calcium channels and their role in flow sensing. Pflugers Arch. 2015;467:157-165.
Pearce D, et al. Collecting duct principal cell transport processes and their regulation. Clin J Am Soc Nephrol. 2015;10:135-146.
Bernardo JF, Friedman PA. Renal calcium metabolism. In. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney:
CHAPTER 36 Potassium, Calcium, and Phosphate Homeostasis
Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2225.
Berndt TJ, Kumar R. Clinical disturbances of phosphate homeostasis. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2369.
Malnic G, et al. Regulation of K+ excretion. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:1659.
Murer H, et al. Proximal tubular handling of phosphate. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2351.
Smogorzewski MJ, et al. Disorders of calcium, magnesium, and phosphate balance. In: Taal MW, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia: Saunders; 2012:689.