Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Part 1 Molecular and cellular environment of bone
- 1 Endochondral bone formation and development in the axial and appendicular skeleton
- 2 The role of osteoblasts
- 3 Osteoclasts: characteristics and regulation of formation and activity
- 4 Bone matrix proteins
- 5 Local regulators of bone turnover
- 6 The PTH/PTHrP system and calcium homeostasis
- 7 Vitamin D metabolism
- 8 Sodium-dependent phosphate transport in kidney, bone and intestine
- 9 Molecular genetic analysis of growth factor signaling in bone
- Part II Determinants of peak bone mass
- Part III Pathophysiology of the aging skeleton
- Part IV Clinical aspects of osteoporosis
- Index
8 - Sodium-dependent phosphate transport in kidney, bone and intestine
Published online by Cambridge University Press: 01 June 2011
- Frontmatter
- Contents
- List of contributors
- Preface
- Part 1 Molecular and cellular environment of bone
- 1 Endochondral bone formation and development in the axial and appendicular skeleton
- 2 The role of osteoblasts
- 3 Osteoclasts: characteristics and regulation of formation and activity
- 4 Bone matrix proteins
- 5 Local regulators of bone turnover
- 6 The PTH/PTHrP system and calcium homeostasis
- 7 Vitamin D metabolism
- 8 Sodium-dependent phosphate transport in kidney, bone and intestine
- 9 Molecular genetic analysis of growth factor signaling in bone
- Part II Determinants of peak bone mass
- Part III Pathophysiology of the aging skeleton
- Part IV Clinical aspects of osteoporosis
- Index
Summary
Introduction
Inorganic phosphate (Pi) is a nutrient that is essential for cell function and skeletal mineralization. To accommodate these needs, transport systems have evolved to permit the efficient transfer of Pi anions across hydrophobic membrane barriers. Dietary Pi intake in North America is generally above the RDA and, except for the elderly where low Pi intakes are relatively common, Pi deficiency is unlikely to occur. The major proportion of ingested Pi is absorbed in the small intestine. Hormonal regulation of this process plays only a minor role in the maintenance of Pi homeostasis. Absorbed Pi is either incorporated into organic forms in cells, deposited into bone, or filtered by the kidney. Under normal conditions, only a small percentage of ingested Pi is retained and most of the absorbed Pi is excreted in the urine. The kidney is a major determinant of Pi homeostasis and tubular handling of Pi is subject to regulation by Pi intake and metabolic requirement. The molecular mechanisms involved in these processes are complex and are currently being investigated.
The present chapter will summarize our current knowledge of the cellular and molecular mechanisms involved in the transport of Pi by kidney, bone and intestine. Citations to review articles will be provided where possible.
- Type
- Chapter
- Information
- The Osteoporosis Primer , pp. 102 - 113Publisher: Cambridge University PressPrint publication year: 2000