engleski

Effects of iron on activity of enzymes glucose-6-phosphate dehydrogenase and lactate dehydrogenase

Iron is an essential element, though the presence of even the smallest quantities of free iron in the cell leads to the creation of free radicals, which can react, with a wide spectrum of cell components and result in damage. The aim of this study was to monitor iron accumulations in liver tissue under conditions of chronic exposure to low iron concentrations and to determine the effect of such on the activity of the enzymes G6PDH and LDH. Carp (Cyprinus carpio L.) were held for 61 days in aquaria with constant iron concentrations (1 mg/L) in the form of iron-dextran. Iron was detected in the paraffin sections of liver tissue using the histochemical Pearl´s method. Histochemical evidence of enzymes activity was determined on cryostat sections of fresh non-fixed tissue. Iron deposition in liver tissue was first detected in the macrophages following the 21st day of treatment. From the 28th day, iron was detected in both the macrophages and the hepatocytes. Continued treatment increased the quantity of depositions. Strong G6PDH activity was detected in the hepatocytes of non-treated carp in the not numerous grains. With continued iron treatment, the number of grains and intensity of reaction was reduced. Reduced activity was noted from the 9th day and continued to the end of treatment. LDH activity in non-treated carp was poor and located in the grains. During treatment, that activity became even weaker and the number of grains reduced. Besides the grains, diffuse LDH activity was detected in the cytoplasm, which increased throughout the treatment. The results indicate that long-term exposure to low iron concentrations causes reduction of enzymes activity in grains and increases in the cytoplasmic activity of LDH.

iron; glucose-6-phosphate dehydrogenase; lactate dehydrogenase; carp; liver

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