{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T18:06:42Z","timestamp":1777918002907,"version":"3.51.4"},"reference-count":0,"publisher":"S. Karger AG","license":[{"start":{"date-parts":[[2008,12,19]],"date-time":"2008-12-19T00:00:00Z","timestamp":1229644800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"},{"start":{"date-parts":[[2008,12,19]],"date-time":"2008-12-19T00:00:00Z","timestamp":1229644800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nephron"],"abstract":"Altered renal cellular phosphate (P<sub>i<\/sub>) homeostasis may be involved in disturbed regulation of l\u03b1,25-dihydroxyvitamin D<sub>3<\/sub> [1,25(OH)<sub>2<\/sub>D<sub>3<\/sub>] production in chronic renal failure. To assess cytoplasmic concentrations of P<sub>i<\/sub> and other phosphate metabolites in uremia, phosphorus-magnetic resonance spectroscopy (31P-MRS) studies were carried out in vivo in rat remnant kidney. Five-sixths-nephrectomized animals (Nx, n = 8, serum creatinine 1.28 \u00b1 0.18 mg\/ dl) and sham-operated control animals (n = 8) were pair-fed a high-phosphate diet (1.6% phosphate, 1.0% calcium) for 19 days. In both remnant and intact kidneys, 31P-magnetic resonance spectra displayed six major peaks: phospho-monoesters (PME), P<sub>i<\/sub>, phosphodiesters, and adenosine triphosphate (ATP)-\u03b3 -\u03b1, and -\u03b2. Phosphocreatine was absent. The relative intensity of the renal \u03b3ATP signal was comparable between the remnant kidney in Nx and the sham-operated kidney in control animals and was, therefore, used as the internal standard to assess the P<sub>i<\/sub>\/\u03b3ATP ratio. The P<sub>i<\/sub>\/\u03b3ATP ratio was significantly (p < 0.05) increased in the remnant kidney as compared to the sham-operated control kidney (0.97 \u00b1 0.24 in Nx vs. 0.75 \u00b1 0.12 in sham-operated controls; means \u00b1 SE). Similarly, the PME\/\u03b3ATP ratio was significantly increased in Nx (p < 0.01), whereas the relative intensities of other phosphate metabolite signals were not altered in Nx. Mean serum 1,25(OH)<sub>2<\/sub>D<sub>3<\/sub> concentrations were 62 pg\/ml for Nx and 93 for sham-operated controls (p < 0.05); mean serum phosphate levels were 4.35 mmol\/l for Nx and 2.61 for sham-operated controls (p < 0.01). The pH in the remnant kidneys was 7.20 \u00b1 0.06 (mean \u00b1 SE, n = 8), whereas the pH in intact kidneys was 7.29 \u00b1 0.05 (n = 8, p < 0.05). To examine the contribution of blood cells to 31P-magnetic resonance spectra, an exchange transfusion with a fluorocarbonated oxygen carrier (to a final hematocrit of 8%) was carried out, while animals (n = 5) were monitored by MRS. This did not significantly change the relative intensities of phosphate metabolite peaks, indicating that blood phosphorus did not measurably contribute to the renal P<sub>i<\/sub> signal. The data suggest that intrarenal P<sub>i<\/sub> concentration is elevated in renal failure. This could inhibit 25-hydroxyvitamin D<sub>3<\/sub>-1 \u03b1-hydroxylase activity and thus have some relevance for pathogenesis of renal hyperparathyroidism.<\/jats:p>","DOI":"10.1159\/000188994","type":"journal-article","created":{"date-parts":[[2008,12,24]],"date-time":"2008-12-24T09:00:08Z","timestamp":1230109208000},"page":"27-33","source":"Crossref","is-referenced-by-count":1,"title":["Renal 31-Phosphorus-Magnetic Resonance Spectral Changes in Experimental Uremia"],"prefix":"10.1159","member":"127","published-online":{"date-parts":[[2008,12,19]]},"container-title":["Nephron"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000188994","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T18:28:38Z","timestamp":1777660118000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000188994"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,12,19]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1159\/000188994","archive":["Portico"],"relation":{},"ISSN":["1660-8151","2235-3186"],"issn-type":[{"value":"1660-8151","type":"print"},{"value":"2235-3186","type":"electronic"}],"subject":[],"published":{"date-parts":[[2008,12,19]]}}}