ISSN:
1432-2013
Schlagwort(e):
Isolated perfused kidney
;
Radioimmunoassay
;
Hypoxia
;
Renal oxygen sensing
;
cAMP
;
cGMP
;
Calmodulin
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract In this study we have investigated the role of oxygen delivery and of classic second messengers on erythropoietin production by the isolated perfused rat kidney. We found that the rat kidney was capable of de novo synthesis of erythropoietin. The erythropoietin production rate was inversely related to the oxygen pressure in the perfusate and increased from 0.17 to 1.85 U erythropoietin h−1 g kidney−1 when arterial PO2 was lowered from 500 mmHg to 30 mmHg. Addition of forskolin (10 μM) and 8-bromo-cGMP (100 μM) to the perfusate elicited significant effects on the renal vascular resistance, but had no significant effect on erythropoietin production. Hypoxia-induced erythropoietin formation, however, was blocked by calmidazolium (1 μM) and W-7 (10 μM), two structurally different putative calmodulin antagonists. Calmidazolium and W-7 had no effect on other functional parameters of the isolated perfused rat kidney such as flow rate, glomerular filtration rate or sodium reabsorption. Our findings suggest that the oxygen-sensing mechanism that controls renal erythropoietin production is primarily located in the kidney itself. A calcium/calmodulin-dependent cellular reaction could be involved in the signal transduction process.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00370520
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