Acta Pharm. 51 (2001) 241-250

Effects of ochratoxin A on Na,K-ATPase activity in rat kidney

JOZSEF PETRIK^1*,  IVANA CEPELAK¹,  STJEPAN PEPELJNJAK², BOZICA RADIC³, 
RENATA ZRINSKI¹  and TIHANA ZANIC-GRUBISIC¹

jozef.petrik@fbf.tel.hr

¹Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, University of Zagreb,
P.O. Box. 156, Zagreb, Croatia
²Department of Microbiology, Faculty of Pharmacy and Biochemistry, P.O. Box. 156, Zagreb, Croatia
³Institute for Medical Research and Occupational Health, Zagreb, Croatia

Proximal tubule cells are regarded as the main intrarenal target of ochratoxin A (OTA). We followed the effects of OTA on Na,K-ATPase activity of basolateral membranes using an animal model of subchronical intoxication. OTA concentration was determined in serum, urine and in kidney tissue. Total body mass and relative kidney mass (kidney mass/body mass) were affected by OTA treatment. During the experiment OTA-treated rats had a reduced body mass gain compared to control values. Comparison of the relative kidney mass showed a significant retardation of 13% only after 35 days of exposure. The 24-urine volume was significantly increased (32%) after 10 days of treatment. Subchronic administration of low doses of OTA produced significant changes in renal proximal tubular cells. The activity of Na,K-ATPase increased significantly (by 24%) in animals treated with OTA during 35 days. Such an increase might be considered as an indicator of a toxicological change and is connected with the activation of the compensatory mechanisms in the proximal tubule.

Keywords: basolateral membrane, Na,K-ATPase, ochratoxin A, proximal tubule cells, rat kidney