Reduced renal sodium excretion in walker-256 tumor-bearing rats

ABSTRACT

Subcutaneous inoculation of Walker-256 tumor is followes by an asymptomatic period which is widely variable in duration, after which, paraneoplastic effects appear suddenly in the form of progressive and rapidy changing homeostatic alterations. Multifocal inoculation of tumor cells in each animal, was carried out with data averaging in each (sub-clinical [SubC], moderate [mCP] and grave [gCP] clinical phases and compared to foodrestrieted FR. The renal sites involved were studied in awake unrestrained animals by measure of sodium, cratinine and lithium clearance. Results indicated an initial increase of both absolute proximal (mCP21.4+1.7 vs FR 16.0+1.1 mmol/min/100 g.b.w., p<0.05) and postproximal (mCP11.1+0.4 vs FR6.6+0.4 mmol/min/100g g.b.w., p<0.001) Na+ reabsorption, which were partially compensated by a rise in glomerular filtration rate (mCP213+11.4 vs FR 162+10.2p1/min/100 g.b.w., p<0.01) and by fell of fractional proximal Na+ reabsorption (mCP62.8+ vs FR 70.1+1.7 per cent, p<0.05), despite this a significant Na+ and fluid retention was observed. Additionally, this study shows that terminal phase of the illness (gCP) culminated with a marked decrease in the creatinine clearance suggesting a significant fall of the renal function.