ISSN:
1437-7799
Keywords:
Key words Extracellular phosphate
;
Hypophosphatemic mice
;
Adenosine 3′,5′-cyclic monophosphate
;
Parathyroid hormone
;
X-linked hypophosphatemic rickets
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Background. To clarify the pathophysiological features associated with phosphate depletion in hypophosphatemic (Hyp) mice, we examined the effect of extracellular phosphate on parathyroid hormone (PTH)-stimulated adenosine 3′,5′-cyclic monophosphate (cAMP) production in the proximal convoluted tubules (PCT). Methods. PTH-Stimulated cAMP production and ATP content were determined by radioimmunoassay and luciferin-luciferase chemiluminescence methods, respectively. Results. The level of cAMP stimulated by PTH at an extracellular phosphate concentration of 0.78 mM was lower in the Hyp mice than in normal mice. The PTH-stimulated cAMP production in the Hyp mice was increased when the extracellular phosphate concentration was raised. In contrast, an increase in extracellular phosphate did not affect the PTH-stimulated cAMP production in the normal mice. Although the ATP content of the PCT was not different between the normal and Hyp mice immediately after microdissection, after 60 min of incubation, it had decreased to a greater extent in Hyp mice than in the normal animals. Raising the extracellular phosphate concentration from 0.78 to 2.3 mM prevented the decrease in ATP content in Hyp mice, and the intracellular ATP content then became comparable to that in the normal control. Conclusions. These results suggest that ATP content in the PCT tended to be decreased in Hyp mice by a decreased phosphate supply and that the blunted effect of PTH on cAMP production in these mice is due to ATP depletion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s101570050055
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