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Early decreases in pulmonary, hepatic and renal glutathione levels in response to cadmium instillation into rat trachea
Author(s) -
Iguchi Hiroshi,
Ikeda Masayuki,
Kojo Shosuke
Publication year - 1991
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.2550110310
Subject(s) - glutathione , lung , cadmium , kidney , chemistry , medicine , endocrinology , metallothionein , cadmium chloride , toxicity , biology , biochemistry , enzyme , organic chemistry
After instillation of cadmium (Cd) into the rat trachea, reduced and oxidized glutathione (GSH and GSSG) levels in the lung, liver and kidney were studied in relation to Cd concentrations and metallothionein (Mt) contents. Rats instilled with Cd developed haemorrhagic pneumonia, which deteriorated with a marked swelling of the lung throughout the experimental period of 48 h. The total glutathione (GSH + GSSG) level in the organs decreased after 6 h to 60–70% of the control levels. The decreased glutathione level was never restored to the control level within 48 h in the lung, and was possibly due to the pneumonia. Completely recovered glutathione was seen in other organs. The GSSG level did not decrease significantly in the lung or liver but lowered significantly after 12 h and 24 h. The GSSG fraction in the amount of total glutathione was 10% or more in the lung and 5% or less in the liver or kidney. This finding indicated that the total glutathione level was mainly changed by the decrease in the GSH fraction. Cadmium in the lung increased to 7.3 ppm 3 h after Cd instillation and decreased to 2.5 ppm within 48 h. Cadmium in the liver and kidney gradually increased with time, and after 48 h reached 1.1 and 2.3 ppm, respectively. This indicated a transportation of Cd from the lung to these organs. Moreover, the early stage of Cd accumulation coincided with the total glutathione decrease in the organs. After Cd instillation, pulmonary, hepatic and renal Mt started to increase at 3 or 6 h, and markedly increased at 24 h or later. After 48 h, the Mt concentration was similar in both the lung and liver, but was 2.5‐fold higher than in the kidney. These increases appeared to depend on the time that elapsed after Cd instillation, and not on the Cd concentration or glutathione level in each organ. It appears that Cd initially acted to decrease the glutathione level in the organs and then caused Mt synthesis, because the glutathione level was decreased at an early stage of Cd accumulation and preceded an apparent increase in Mt synthesis.