Where is calcium excreted

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July 21, Understanding Bone Density Results January 13, American Bone Health and Susan G. Cancer and Bone Health February 26, Subscribe to our mailing list. Facebook-f Twitter Youtube. About Us. FGF23 is primarily expressed in the osteoblasts and osteocytes. Because Fgf23 knockout mice showed very similar phenotype to Klotho knockout mice including severe hyperphophatemia and osteoporosis, and gain of function mutation of Fgf23 gene was observed in ADHR patients.

The main studies about the role of FGF23 in the kidney have focused on phosphate metabolism rather than calcium metabolism 23 , Fibroblast growth factor 23 FGF23 in the kidney. It might also stimulate parathyroid hormone PTH secretion in parathyroid glands. However, the exact mechanism how FGFklotho regulates renal phosphate excretion is still unknown.

Recently, FGF23 was suggested as a potential biomarker for management of phosphate balance in chronic kidney disease CKD patients because the circulating FGF23 level was higher in CKD patients than healthy controls and the increased FGF23 level was an independent risk factor for higher mortality among dialysis patients FGF23 also plays some roles in the parathyroid glands and other organs like the choroid plexus, pituitary gland, and bone.

However, further studies are needed to clarify the roles and the mechanisms. The kidney has been known as the central organ for calcium homeostasis through fine regulation of renal calcium excretion. For the past decade, there has been big progress in the understanding of the roles of the kidney in calcium homeostasis. The identification of calcium transport proteins and the molecular approach to the regulatory mechanisms achieved a major contribution to this progress.

Klotho and FGF23 emerged as new players in calcium metabolism in the kidney. Thus, the role of the klotho-FGF23 axis in the regulatory mechanisms of calcium transport needs to be addressed. National Center for Biotechnology Information , U. Journal List Electrolyte Blood Press v. Electrolyte Blood Press. Published online Dec Un Sil Jeon , M. Find articles by Un Sil Jeon. Author information Article notes Copyright and License information Disclaimer.

Corresponding author. Corresponding author: Un Sil Jeon, M. Received Oct 6; Accepted Nov This article has been cited by other articles in PMC. Abstract Plasma calcium concentration is maintained within a narrow range 8. Keywords: kidney, TRPV cation channels, klotho, fibroblast growth factor Introduction The maintenance of calcium homeostasis is very important because calcium is the main component of bony skeleton and serves as the intracellular and extracellular messenger in numerous essential cellular events such as neuronal network, immune response, muscle contraction, and hormone secretion.

Open in a separate window. New players of renal calcium handling During the past decade, two new proteins; klotho and fibroblast growth factor 23 FGF23 emerged as the new players of calcium, magnesium, and phosphate metabolism. Klotho Klotho [Clotho] was the youngest of the Moirae of Greek mythology three sisters who determined the destiny and life of humans; Clotho, Lackesis and Atropos and the "spinner" who controlled the thread of life.

FGF23 FGF23, a member of the FGF family type I transmembrane phosphotyrosine kinase receptors , is a 30 kDa secreted protein and inactivated by cleavage into two smaller fragments N-terminal 18 kDa fragment and C-terminal 12 kDa fragment by a pro-convertase enzyme, furin Fig. Conclusion The kidney has been known as the central organ for calcium homeostasis through fine regulation of renal calcium excretion. References 1.

In: Brenner BM, editor. Philadelphia: J Am Soc Nephrol. Effects of furosemide on renal calcium handling. Am J Physiol Renal Physiol. Kidney Int. Mechanistically, parathyroid hormone preserves blood calcium by several major effects:. Vitamin D acts also to increase blood concentrations of calcium.

It is generated through the activity of parathyroid hormone within the kidney. Far and away the most important effect of vitamin D is to facilitate absorption of calcium from the small intestine. In concert with parathyroid hormone, vitamin D also enhances fluxes of calcium out of bone. Calcitonin is a hormone that functions to reduce blood calcium levels.

It is secreted in response to hypercalcemia and has at least two effects:. Although calcitonin has significant calcium-lowing effects in some species, it appears to have a minimal influence on blood calcium levels in humans. A useful way of looking at how hormones affect tissues to preserve calcium homeostasis is to examine the effects of calcium deprivation and calcium loading.

The following table summarizes body responses to conditions that would otherwise lead to serious imbalances in calcium and phosphate levels in blood.

Thyroid and Parathyroid Glands: Introduction and Index.