engleski

Effect of ochratoxin A on enzyme activity and malondialdehyde in rat urine

Mycotoxin ochratoxine A (OTA)is a wellknown nephrotoxic compound. The aim of the study was to check the time-cours of representative kidney brush-border and cytosolic enzymes released in urine and concentration of malondyaldehide (MDA) in urine during and after OTA treatment. Adult rats were receiving i.p. doses of 500 ug/kg b.w. of OTA three times a week for four weeks, and their urine was collected after the 1th, 3th, 6th, 9th, and 12th dose, and 14 and 21 days after the 12th dose (follow up). 24-hour urine measurements included the catalytic activity of alkaline phpsphatase (AP), leucine aminopeptidase (LAP), lactate dehydrogenase (LDH), and isocitrate dehydrogenase (ICDH) and concentrations of OTA and MDA. OTA affects all parameters measured in urine. After the 6th dose, the concentration of MDA and the catalytic activity of AP, LAP, LDH, and ICDH reached their peak (278, 195, 680, 730, 346% respectively) and were significantly different from controls (p < 0.05). However, althought the rats received 6 more doses of OTA, all measured parameters showed a declining trend. The catalytic activity of brush-border enzymes LAP and AP were significantly higher for a longer period than of LDH and ICDH. The 21-day follow.up urine volume, concentration of creatinine and MDA, as wellas the activity of all measured enzymes did not differ from controls. The effect of OTA-induced release of brush-border enzymeis more pronounced than that of cytosolic enzymes. The catalytic activity of brush-border and cytosolic enzymes released to urine, as well as urinary MDA concentration reverted to control values 21 days after the end of treatment.

ochratoxin A; urine; enzymes; malondialdehyde; creatinine

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