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Horm Metab Res 1998; 30(2): 88-92
DOI: 10.1055/s-2007-978842
Originals Clinical

© Georg Thieme Verlag Stuttgart · New York

Parathyroid Hormone Activity Increases During Endotoxemia in Conscious Rats

T. Nakamura, Y. Mimura, K. Uno, M. Yamakawa
  • Endocrine Unit, Third Department of Surgery, University of Tokyo
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1996

1997

Publikationsdatum:
20. April 2007 (online)

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Abstract

Our previous studies showed that the phosphaturic effect of parathyroid hormone (PTH) is blunted during acute-phase endotoxemia in anesthetized rats. However, the possibility that the antiphosphaturia was secondary to hyponatriuresis due to endotoxin (Et)-induced acute renal failure could not be ruled out. The objective of this study was to evaluate phosphate (Pi) excretion during early- and late-phase endotoxemia in conscious rats fed by total parenteral nutrition. Male Wistar rats weighing 270 g were used. Urine samples were taken to determine the Pi excretion rate for 12 h just after Et (E. coli B055) challenge (early-phase endotoxemia), and for 12 h after a 36-h recovery period following Et challenge (late-phase endotoxemia). Rats given isovolumetric saline instead of Et served as controls. Et injection reduced endogenous creatinine clearance markedly (0.88 ± 0.12 ml/min, P < 0.0001, n = 7) and caused hyponatriuresis (0.80 ± 0.19 µl/min, P < 0.001) compared with saline injection (1.78 ± 0.10 ml/min and 3.12 ± 0.39 µl/min, respectively, n = 8) during the early phase. Greater phosphaturia and hypocalciuria were observed simultaneously during early- (Pi excretion = 4.18 ± 1.38 µg/min, P < 0.05; calcium excretion = 0.70 ±0,14 µg/min, P<0.05) and late-phase (4.76 ± 1.72 µg/min, P<0.05; 0.60 ± 0.18 µg/min, P < 0.05, respectively) endotoxemia (n = 8) in comparison with the respective control values (1.61 ± 0.39 and 1.40 ± 0.21 µg/min, early; 0.34 ± 0.14 and 1.97 ± 0.55 µg/min, late, n = 6). Et administration resulted in a significantly increased plasma PTH concentration during the late phase (34.7 ± 7.0 pg/ml, P < 0.05) compared with saline administration (15.4 ± 2.4 pg/ml). In conclusion, these data suggest that the hyperphosphaturia during endotoxemia lasting longer than 12 h is attributable to elevated PTH secretion.

Key words

Calcium excretion - Endotoxemia - Parathyroid hormone - Phosphate excretion - Renal function - Sodium excretion

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