Toxicology 1996 Aug 1;112(1):11-7

Influence of dietary protein levels on the acute toxicity of
methylmercury
in mice.

Adachi T, Yasutake A, Eto K, Hirayama K

Department of Basic Medical Scienes, National Institute for Minamata
Disease, Kumamoto, Japan.

The influence of dietary protein levels on the acute toxicity of
methylmercury (MeHg) was investigated using C57BL/6N male
mice fed either a 24.8% protein diet (normal protein diet, NPD) or a
7.5% protein diet (low protein diet, LPD). When MeHg
was administered to each group of mice, all mice died at a medium or
high dose (80 or 120 mumol/kg, respectively) within 16
or 7 days, respectively, but not at a low dose (40 mumol/kg) in both
dietary groups. Although no difference was observed in the
survival rate at a medium dose, NPD-fed mice died earlier despite
lower
brain Hg than LPD-fed mice at a high dose.
Accordingly, death, in our observations, could not be due to neural
damage by MeHg. When a high dose of MeHg was
administered to mice, plasma aspartate aminotransferase and alanine
aminotransferase activities increased in NPD-fed mice but
not in LPD-fed mice in spite of similar hepatic Hg levels. Therefore,
the higher susceptibility of the liver could be reason for the
shorter survival period in NPD-fed mice. Since plasma creatinine
increased within 24 h after MeHg administration at a medium
or high dose, renal dysfunction could be a major factor in death. The
present results suggest that susceptibility to acute MeHg
toxicity was higher in NPD-fed mice than in LPD-fed mice, possibly due
to the difference in hepatic susceptibility.

PMID: 8792844, UI: 96384984