Charles-Shannon V L, Sasser L B, Burbank D K, Kelman B J
Proc Soc Exp Biol Med. 1981 Oct;168(1):56-61. doi: 10.3181/00379727-168-41234.
The ontogeny of hepatic metallothioneins (Mt) in fetal tissue as related to dietary and hepatic Zn was investigated. Sixty 6-month-old female rats were divided into two groups and given either double-distilled water or water containing 700 mug of Zn per milliliter. Dams from each group were killed on 16, 19, or 21 days of gestation, and maternal and fetal livers were removed. Mt content of the tissue was estimated by Piotrowski's Hg-saturation method. Results established the presence of an endogenous hepatic Mt in the fetal rat as early as 16 days of gestation. We further demonstrated a marked progressive increase in fetal Mt from Day 16 through gestation accompanied by a decrease in maternal hepatic Mt. It is suggested that Zn increased fetal Mt by inducing fetal synthesis, redistributing fetal Mt, or increasing Mt transport to the fetus, because both fetal and maternal hepatic Mt were increased. Fetal hepatic Mt concentration was several times greater than maternal Mt at corresponding stages of gestation. Mt may serve to either ensure adequate storage of Zn or Cu for fetal development or protect the fetus against metal toxicity, but the significance of these high endogenous levels of fetal Mt are not clear at this time.
研究了胎儿组织中肝脏金属硫蛋白（Mt）的个体发生与饮食及肝脏锌的关系。将60只6月龄雌性大鼠分为两组，分别给予双蒸水或每毫升含700微克锌的水。每组的母鼠在妊娠第16、19或21天处死，取出母鼠和胎儿的肝脏。用皮奥特罗夫斯基的汞饱和法估计组织中的Mt含量。结果表明，早在妊娠第16天，胎鼠肝脏中就存在内源性Mt。我们进一步证明，从妊娠第16天到妊娠结束，胎儿Mt显著逐渐增加，同时母鼠肝脏Mt减少。由于胎儿和母鼠肝脏的Mt都增加了，因此推测锌通过诱导胎儿合成、重新分布胎儿Mt或增加Mt向胎儿的转运来增加胎儿Mt。在妊娠相应阶段，胎儿肝脏Mt浓度比母鼠Mt浓度高几倍。Mt可能有助于确保为胎儿发育充分储存锌或铜，或保护胎儿免受金属毒性影响，但目前尚不清楚胎儿Mt这些高内源性水平的意义。
