engleski

Endogenous digitalis-like factors in rat sera during ochratoxicosis

In this study we determined the concentration of endogeneous digitalis-like factors (EDLFs) in rats treated with ochratoxin A (OA). The presence of a highly conserved An, K-ATPase binding domain for cardiac glycoside drugs implies the existence of natural ligands that act as endogenous mogulator(s) of this enzyme. Alteration of Na, K-ATPase activity by inhibitors may play a key role in many fundamental physiological processes (e.g. vascular contractility, control of sodium in the kidney). Pathological conditions in animals and humans involving salt and water homeostasis have been associated with alteration of Na, K-ATPase activity and/or the presence of endogeneous digitalis-like factors. OA is a potent nephrotoxic, hepatotoxic, genotoxic and carcinogenic agent, and it cound interfere with the normal blood coagulation and immune response. This windespread mycotoxin contamines animal feed and human blood. We have followed the effects of low doses of OA (120 ug/kg b.w.) during 10 and 35 days. The experiments were performed on the female rats of Wistar strain (9-10 weeks old: n=24). In our experiments we determined the concentrations of EDLFs (serum) and OA (serum, urine, kidney cortex), and the activity of Na, K-ATPase (basolateral membrane of proximal tubular cells from kidney cortex).The concentration of OA in kidney cortex was found to be 32 ng/g tissue and 48ng/g tissue after 10 and 35 days of experiment, respectively. Treatment lasting for 10 days did not produced a significant changes in EDLFs concentration or in Na, K/ATPase activity. However, the concentration of EDLFs increased to 243% and the activity of Na, K-ATPase to 124% after the 35 days of tretment. Weconclude that OA in concentration of 120 ug/kg b.w./days causes the low level of renal proximal tubular cell injury, characterized by changed activity of Na, K-ATPase.

ochratoxin A; endogeneous digitalis-like factors

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