Suzuki K T, Tamagawa H, Takahashi K, Shimojo N
National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan.
Toxicology. 1990 Mar 16;60(3):199-210. doi: 10.1016/0300-483x(90)90143-5.
Our investigations undertook to examine whether copper (Cu) and zinc (Zn) bound to renal metallothionein (MT) along with cadmium (Cd) in Cd-loaded rats can be mobilized during pregnancy and lactation. Rats of the Wistar strain were injected with Cd. Synthesis of MT containing Cd, Cu and Zn was induced in the kidneys. Concentrations of Cd and essential elements in blood plasma and organs (liver and kidneys) were compared among non-pregnant and pregnant, and Cd-loaded and non-loaded rats at middle and late gestational days and after delivery. Cu bound to renal MT was decreased with gestational age, while Zn was slightly increased. The results indicate that Cu was mobilized and utilized even when the metal was bound to MT in the kidneys of dams. On the other hand, Zn bound to renal MT in Cd-loaded rats was retained and not mobilized during pregnancy. The elution profile of renal MT on an SW column was changed from a typical renal to a mixed profile of renal and hepatic MTs as a result of decreased Cu content in MT. Plasma essential elements changed similarly with gestational age in both concentrations and distributions in non-loaded and Cd-loaded rats. These results indicate that the 3 metals bound to renal MT are dealt with differently during gestation and lactation, and Cu but not Zn is transferred to the fetus, independently of the Cd status of the dam.
我们的研究旨在探讨镉负荷大鼠肾脏中与金属硫蛋白（MT）结合的铜（Cu）、锌（Zn）以及镉（Cd）在妊娠和哺乳期是否会被动员。给Wistar品系大鼠注射镉。诱导肾脏中合成含镉、铜和锌的金属硫蛋白。比较非妊娠和妊娠的镉负荷和未负荷大鼠在妊娠中期、晚期及分娩后血浆和器官（肝脏和肾脏）中镉及必需元素的浓度。与肾脏金属硫蛋白结合的铜随胎龄增加而减少，而锌略有增加。结果表明，即使金属与母鼠肾脏中的金属硫蛋白结合，铜仍会被动员和利用。另一方面，镉负荷大鼠肾脏中与金属硫蛋白结合的锌在妊娠期间被保留且未被动员。由于金属硫蛋白中铜含量降低，肾脏金属硫蛋白在SW柱上的洗脱图谱从典型的肾脏型变为肾脏型和肝脏型金属硫蛋白的混合图谱。未负荷和镉负荷大鼠血浆中的必需元素在浓度和分布上随胎龄变化相似。这些结果表明，与肾脏金属硫蛋白结合的三种金属在妊娠和哺乳期的处理方式不同，铜而非锌会转移至胎儿，且与母鼠的镉状态无关。
