RESUMO
In the present study, the concentration of trace elements, total mercury (Hg) and selenium (Se) and mercury forms (MeHg, Hginorg and HgSe) in the vulnerable coastal dolphins Pontoporia blainvillei and Sotalia guianensis were appraised and compared, using metallothioneins (MT) and glutathione (GSH) as biomarkers for trace element exposure. The trace element concentrations varied between muscle and liver tissues, with liver of all dolphin specimens showing higher Hg and Se concentrations than those found in muscle. Hg, MeHg and Hginorg molar concentrations showed a clear increase with Se molar concentrations in the liver of both dolphins, and Se concentrations were higher than those of Hg on a molar basis. Se plays a relevant role in the detoxification of MeHg in the hepatic tissue of both dolphins, forming Hg-Se amorphous crystals in liver. In contrast, MT were involved in the detoxification process of Hginorg in liver. GSH levels in P. blainvillei and S. guianensis muscle tissue suggest that these dolphins have different diving capacities. Muscle Hg concentrations were associated to this tripeptide, which protects dolphin cells against Hg stress.
Assuntos
Mergulho/fisiologia , Golfinhos/metabolismo , Glutationa/metabolismo , Mercúrio/análise , Metalotioneína/metabolismo , Selênio/análise , Poluentes Químicos da Água/análise , Animais , Biomarcadores/metabolismo , Brasil , Feminino , Inativação Metabólica , Fígado/metabolismo , Masculino , Mercúrio/farmacocinética , Compostos de Mercúrio/análise , Compostos de Mercúrio/farmacocinética , Compostos de Metilmercúrio/análise , Compostos de Metilmercúrio/farmacocinética , Músculos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Selênio/farmacocinética , Compostos de Selênio/análise , Compostos de Selênio/farmacocinética , Oligoelementos/análise , Oligoelementos/farmacocinética , Poluentes Químicos da Água/farmacocinéticaRESUMO
DMPS (2,3-dimercaptopropane-1-sulfonate, Na salt), when used as a challenge test for mercury in workers involved in the production of a calomel skin-bleaching lotion and in direct contact with mercurous chloride, elevated urine levels of mercury. A DMPS treatment regimen was devised and initiated. Three days after the challenge test, DMPS was administered p.o. (400 mg per day) for 8 days, followed by a no-treatment period of five days. A new cycle of DMPS treatment for 7 days was initiated and followed by 5 days without treatment. A third period of treatment was begun for 6 days, followed by a 5-day no-treatment period. The urinary mercury greatly increased during those periods when DMPS was administered (1754, 314, and 173 microgram/24 h for the periods 1, 2 and 3, compared with 106, 48 and 53 microgram/24 h on the corresponding no-treatment periods). One of the workers presented signs of drug intolerance and was discharged after receiving the first cycle of treatment. DMPS treatment was effective in lowering the body burden of mercury and in decreasing the urinary mercury concentration to normal levels.