Normal handling of phosphate in the salivary glands of X-linked hypophosphataemic mice

Delzer, Pamela R.; Meyer, Ralph A.

doi:10.1016/0003-9969(84)90148-1

Cited by 6 publications

(1 citation statement)

References 21 publications

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“…The level of phosphate ions in unstimulated whole saliva is substantially higher than that found in the blood (Shannon et al 1962;Macgregor and Edgar 1986;Ferguson 1988;Agha-Hosseini et al 2006). This appears to be due to active ion transport (Delzer and Meyer 1984), and MEPE has previously been shown to be expressed also in the salivary gland (Ogbureke and Fisher 2004). Unlike the kidney and salivary gland where phosphate is actively transported, neither the sweat gland nor the lacrimal gland is thought to do so.…”

Section: Discussionmentioning

confidence: 98%

SIBLING Expression Patterns in Duct Epithelia Reflect the Degree of Metabolic Activity

Ogbureke

Fisher

2007

J Histochem Cytochem.

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The SIBLING (Small Integrin-Binding LIgand, N-linked Glycoprotein) family of secreted glycophosphoproteins includes bone sialoprotein (BSP), dentin matrix protein-1 (DMP1), dentin sialophosphoprotein (DSPP), osteopontin (OPN), and matrix extracellular phosphoglycoprotein (MEPE). For many years, they were thought in normal adults to essentially be limited to metabolically active mesenchymal cells that assembled the mineralized matrices of bones and teeth. Over the last decade they have also been upregulated in a variety of tumors. Three of these proteins (BSP, OPN, and DMP1) have been shown to interact with three matrix metalloproteinases (MMP-2, MMP-3, and MMP-9, respectively). Recently, all five SIBLINGs and their MMP partners when known were observed in specific elements of normal ductal epithelia in salivary gland and kidney. We have hypothesized that the SIBLINGs and their MMP partners may be expressed in ductal cells with high metabolic activity. In this paper, we show that all the SIBLINGs (except MEPE) and their MMP partners are expressed in the metabolically active epithelia of human eccrine sweat gland duct but not in the more passive ductal cells of the macaque (monkey) lacrimal gland. It is hypothesized that MEPE expression may be limited to cells involved in active phosphate transport. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.

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Section: Discussionmentioning

confidence: 98%

SIBLING Expression Patterns in Duct Epithelia Reflect the Degree of Metabolic Activity

Ogbureke

Fisher

2007

J Histochem Cytochem.

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Parabiosis suggests a humoral factor is involved in X-linked hypophosphatemia in mice

Meyer

Gray

1989

Journal of Bone and Mineral Research

193

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Reduced renal tubular reabsorption of phosphate of unknown etiology is characteristic of X-linked hypophosphatemia in both humans and mice. To test whether a humoral abnormality is involved in the renal effect, parabiosis was performed between Hyp and normal mice at 4 weeks of age. The normal mice joined to Hyp mice showed a progressive diminution of plasma phosphate over the next 3 weeks to approach the level of the Hyp mice. These normal mice had a greater renal phosphate excretion index (urine P/plasma P/urine creatinine) than normal-normal pairs, thus suggesting a reduced renal tubular reabsorption of phosphate. At the same time the expected rises in plasma calcium and plasma 1,25-dihydroxyvitamin D did not occur. There was a significant reduction in their femoral mineral content but not in their femoral length or body growth relative to normal-normal pairs. This change in renal handling of phosphate was specific since the urinary losses of potassium and magnesium were not significantly changed. Separation of normal-Hyp pairs 3 or 6 weeks after parabiosis caused the normal mice to achieve normal plasma phosphate levels within 24 h. At 48 h and 7 days after separation these normal mice had plasma phosphate levels higher than normal mice separated from normal-normal pairs. In summary, the data suggest the presence of a phosphaturic factor in the Hyp mice that can cross a parabiotic union into normal mice and induce many of the symptoms of X-linked hypophosphatemia.

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Phosphate transport in immortalized cell cultures from the renal proximal tubule of normal and Hyp Mice: Evidence That the HYP gene locus product is an extrarenal factor

Nesbitt

Econs

Byun

et al. 1995

Journal of Bone and Mineral Research

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Whether renal phosphate wasting in X-linked hypophosphatemia (XLH) results from an intrinsic renal or humoral defect remains controversial. In studies of the murine homolog of XLH, harboring the Simian Virus 40 (SV40) large T antigen, we obviated the influence of renal cell heterogeneity and impressed memory by comparing Na(+)-phosphate cotransport in immortalized cells from the S1 segment of the proximal tubule. Cells from SV40 transgenic normal and Hyp mice exhibit characteristics of differentiated proximal tubule cells including gluconeogenesis and alkaline phosphatase activity. Surprisingly, however, we found two distinct populations of cells from the S1 proximal tubule of both normal and Hyp mice. In one, PTH treatment increases cAMP accumulation, while in the other both PTH and thyrocalcitonin enhance cAMP production. Kinetic parameters for Na(+)-phosphate cotransport were similar in both subpopulations of cells from normal (Km, 0.29 +/- 0.03 vs. 0.39 +/- 0.04 mM; Vmax, 4.6 +/- 0.6 vs. 5.2 +/- 0.4 nmol/mg/5 minutes) and Hyp mice (0.33 +/- 0.02 vs. 0.26 +/- 0.04; 6.0 +/- 0.7, 4.8 +/- 0.6). More importantly, phosphate transport in S1 cells of either subpopulation from Hyp mice is no different than that of normals. These data indicate that renal proximal tubule cells from Hyp mice have intrinsically normal phosphate transport and support the hypothesis that a humoral abnormality underlies renal phosphate wasting in XLH.

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Normal handling of phosphate in the salivary glands of X-linked hypophosphataemic mice

Cited by 6 publications

References 21 publications

SIBLING Expression Patterns in Duct Epithelia Reflect the Degree of Metabolic Activity

SIBLING Expression Patterns in Duct Epithelia Reflect the Degree of Metabolic Activity

Parabiosis suggests a humoral factor is involved in X-linked hypophosphatemia in mice

Phosphate transport in immortalized cell cultures from the renal proximal tubule of normal and Hyp Mice: Evidence That the HYP gene locus product is an extrarenal factor

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