ESPE Abstracts

Inorganic phosphate (Pi) is an essential mineral required for the formation of bone, cell membranes, energy metabolism, storage and transmission of genetic information, cellular signaling events, or acid-base buffering. Diet provides phosphate in various forms ranging from plant-derived phytates with low bioavailability to animal proteins and inorganic phosphate salt with high and very high bioavailability, respectively. Since intestinal absorption of bioavailable phosphate is high and little regulated, endocrine mechanisms and renal excretion are critical to maintain phosphate balance to prevent states of phosphate deficiency or excess. Triggering endocrine signals and renal adaptation to dietary phosphate intake requires mechanisms to sense cellular and systemic phosphate content. Several molecules have been implicated in sensing intra- and extracellular phosphate including the calcium-sensing receptor, phosphate transporters, and intracellular IP6 kinases. Evidence supporting their role will be discussed. The clinical relevance of these systems is illustrated by inborn or acquired diseases that impair endocrine or renal control.