Effect of selenium pre-treatment on cadmium content and enzymatic antioxidants in tissues of suckling rat

Abstracts / Toxicology Letters 164S (2006) S1–S324

one polymorphism; a G → A transition in position 35991 in AS3MT was associated with lower levels of MMA This polymorphism had a high frequency in this population group (allele frequency 76%), with 58% homozygous carriers. We did not find any associations between metabolite pattern and the other genes studied. This finding concludes that AS3MT plays an important role in arsenic metabolism, and polymorphisms in this gene may partly be responsible for the high inter-individual variation in arsenic metabolism and susceptibility. doi:10.1016/j.toxlet.2006.07.053 P14-09 Mercury concentrations in bluefin tunas (Thunnus thynnus) Jelena Pompe Gotal, Emil Prevendar-Crni´c

Sreboˇcan, Andreja

Veterinary Faculty, University of Zagreb, Zagreb, Croatia Levels of total mercury in the muscle (29 samples) and liver tissue (15 samples) of bluefin tuna (Thunnus thynnus) weighing 100–300 kg were determined by cold vapor atomic absorption (AA) spectroscopy. Tunas were previously captured in the waters of Malta, towed to the farm in the Adriatic Sea and fattened defrosted herring and sardine for the period of 6–7 months. The purpose of the investigation was to determine the magnitude of mercury contamination and to ascertain whether the concentrations in muscle tissue exceeded the maximum level fixed by the European Commission Decision (1 ␮g/g wet wt). Total mercury concentrations in muscle tissue of tunas ranged from 0.49 to 1.809 (median 0.899 ␮g/g wet wt) while in liver tissue it was from 0.324 to 3.248 (median 1.165 ␮g/g wet wt). Total mercury concentrations in six samples of sardine ranged from 0.050 to 0.072 ␮g/g wet wt, while two samples of herring contained 0.020 and 0.053 ␮g/g wet wt. Twelve out of 29 (41%) muscle samples of tuna contain mercury above maximum level fixed by the European Commission Decision. It is generally believed that mercury levels in Mediterranean fish are higher than those of the other seas or oceans due to numerous deposits of mercury ores and metallic mercury in surrounding countries. We also have to keep in mind that tunas are highly mobile fish which swim for the whole life what enables them to enter or leave Mediterranean Sea or Atlantic Ocean. doi:10.1016/j.toxlet.2006.07.054

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P14-10 Effect of selenium pre-treatment on cadmium content and enzymatic antioxidants in tissues of suckling rat Maja Lazarus 1 , Tatjana Orct 1 , Maja Blanuˇsa 1 , Krista Kostial 1 , Jasna Pirˇsljin 2 , Blanka Beer-Ljubi´c 2 1 Institute

for Medical Research and Occupational 2 Faculty of Veterinary Health Zagreb Croatia; Medicine, University of Zagreb, Zagreb, Croatia Neonates are a group of special concern regarding higher absorption and retention of cadmium (Cd) compared to adults. Selenium (Se) prevents the toxicity of Cd through still undefined mechanisms. Cadmium has indirect role in free radical generation. Studies have shown that free radical scavengers and antioxidants are useful in protecting against Cd toxicity. This protective effect has not yet been studied in the early postnatal period. The effect of Cd on the activity of two antioxidant enzymes, glutathione peroxidase (GSH-Px) and superoxid dismutase (SOD), was studied in the liver, kidney and brain of suckling Wistar rats. Also, the influence of Se on Cd body burden of sucklings was evaluated. Rats were orally exposed to CdCl2 xH2 O and/or Na2 SeO3 in equimolar amounts from day 6 to day 14 after birth. After 4 days of pre-treatment with Se, rats were concurrently treated for 5 days with Cd and Se (8 ␮mol/kg/day, each). Cadmium exposure had no effect on both SOD and GSH-Px activities in kidney and brain whereas in liver activities were increased. Selenium exposure increased both enzyme activities in all organs (except SOD in liver). Concurrent administration of Se and Cd elevated both enzyme activities in kidney and brain compared to Cd and control group up to the levels found in Se treated animals. The same treatment showed opposite action on tissue Cd content: Se significantly lowered Cd burden in the order liver > kidney > brain. It can be concluded that selenium had positive effect on reduction of Cd body burden as well as on enzyme activities in kidney and brain. doi:10.1016/j.toxlet.2006.07.055 P14-11 Effect of Thiomersal and mercuric chloride on mercury distribution in suckling rats Tatjana Orct, Maja Kostial

Lazarus, Maja

Blanuˇsa, Krista

Institute for Medical Research and Occupational Health, Zagreb, Croatia Thiomersal (ethylmercury) used as preservative in vaccines represents a new aspect in the field of mercury