Abstract
Female rats (65–75 days old) were given orally 0.84 or 3.36 mg Hg/kg as methylmercury chloride (MeHgCl) 5 times a week for 13 and 3 weeks, respectively. The proportion of inorganic to total mercury remained as low as 6% in whole animal though it increased to above 40% in the kidneys.
Differences in organ half times and the negative correlation with time for blood to liver, brain and kidney mercury ratios indicated more than one compartment for MeHg+. Brain had 26 days half time with a 32% final equilibrium concentration in relation to the body concentrations. Brain concentrations of mercury reported on rats dosed repeatedly with MeHg+ agreed with these values which justifies their use when experiments are planned to give a certain brain MeHg+ concentration.
Half time for the whole body was 34 days but pathological changes — weight loss, tubular damage, slow gastrointestinal passage — disturbed the accumulation curves in the higher dose group. Blood to kidney ratio and uptake of MeHg+ by kidneys also changed significantly.
Zusammenfassung
Weibliche Ratten im Alter von 65–75 Tagen erhalten 5mal wöchentlich 0,84 (13 Wochen lang) oder 3.36 mg Hg/kg (3 Wochen lang) als Methylquecksilberchlorid oral. Das Verhältnis des anorganischen zum Gesamtquecksilber beträgt im Ganztier nur 6%, in den Nieren steigt es jedoch über 40%.
Unterschiede in den Organ-Halbwertzeiten und die negative Korrelation der Blut/Leber-, Gehirn und Nieren-Quecksilber-Quotienten mit der Zeit sprechen für mehr als ein Kompartiment für Methylquecksilber. Im Gehirn beträgt die Halbwertzeit 26 Tage mit einer schließlichen Gleichgewichtskonzentration von 32% im Verhältnis zu den Ganzkörper-Konzentrationen. Die Quecksilberkonzentrationen im Gehirn von Ratten nach wiederholter Gabe von Methylquecksilber decken sich mit diesen Werten; damit ist ihre Anwendung gerechtfertigt bei Versuchen, bei denen eine gewisse Methylquecksilber-Konzentration im Gehirn erreicht werden soll.
Die Halbwertzeit im Gesamttier beträgt 34 Tage, aber pathologische Veränderungen — Gewichtsverlust, tubulärer Nierenschaden, Verlangsamung der Passage im Verdauungstrakt — die Sättigungskurven in der höheren Dosierungsgruppe beeinträchtigten. Gleichermaßen werden die Blut/Nieren-Quotienten und die Aufnahme von Methylquecksilber durch die Nieren signifikant verändert.
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Magos, L., Butler, W.H. The kinetics of methylmercury administered repeatedly to rats. Arch Toxicol 35, 25–39 (1976). https://doi.org/10.1007/BF00333983
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DOI: https://doi.org/10.1007/BF00333983