Nishimura H, Nishimura N, Tohyama C
Department of Hygiene, Aichi Medical University, Japan.
J Histochem Cytochem. 1989 May;37(5):715-22. doi: 10.1177/37.5.2703706.
Metallothionein (MT) is a cysteine-rich, low molecular weight protein inducible by heavy metal ions and various endogenous factors. Using an indirect immunofluorescent technique, we studied the localization of MT in developing rat tissues (kidney, small intestine, and liver). In kidney of the neonate and fetus, MT was found in both the cytoplasm and the nucleus of renal tubular epithelia. Localization of MT changed with shift of zonation in the renal cortex during development. Metallothionein was found mainly in the inner zone of the cortex but not in tubules of the neogenic zone on Day 4. Until Day 18, tubular cells containing MT were observed in a part of the cortex adjacent to the medulla, followed by a significant decrease in immunostaining by Day 27. In small intestine of the neonate, MT was localized predominantly in Paneth and goblet cells which play secretory roles. The number of goblet cells with strong immunostaining for MT was maximal on Day 27. In liver of 20-day fetuses and of 4-day-old neonates, both the cytoplasm and the nucleus of hepatocytes exhibited strong immunofluorescence. The intensity of MT staining diminished with development, and by 18-27 days after birth no immunofluorescence was observed in the nucleus. We further studied a possible association of MT with development by localizing MT in livers obtained from partially hepatectomized and laparotomized rats. Hepatectomy led to the appearance of MT not only in the nucleus and cytoplasm of hepatocytes but also in sinusoids and bile canaliculi. After laparotomy, MT immunofluorescence was observed only in the cytoplasm. The present results suggest a possible involvement of MT in cell proliferation and differentiation, as well as in transport and secretion of this metal-binding protein.
金属硫蛋白（MT）是一种富含半胱氨酸的低分子量蛋白质，可由重金属离子和多种内源性因子诱导产生。我们运用间接免疫荧光技术，研究了MT在发育中的大鼠组织（肾脏、小肠和肝脏）中的定位。在新生大鼠和胎儿的肾脏中，MT存在于肾小管上皮细胞的细胞质和细胞核中。在发育过程中，随着肾皮质分区的变化，MT的定位也发生改变。在第4天，MT主要存在于皮质的内层区域，而新生区的肾小管中未发现。直到第18天，在靠近髓质的部分皮质区域观察到含有MT的肾小管细胞，随后在第27天免疫染色显著减少。在新生大鼠的小肠中，MT主要定位于发挥分泌作用的潘氏细胞和杯状细胞。对MT免疫染色强的杯状细胞数量在第27天达到最大值。在20天龄胎儿和4日龄新生大鼠的肝脏中，肝细胞的细胞质和细胞核均呈现强烈的免疫荧光。随着发育，MT染色强度减弱，出生后18 - 27天，细胞核中未观察到免疫荧光。我们通过将MT定位在部分肝切除和剖腹大鼠的肝脏中，进一步研究了MT与发育的可能关联。肝切除不仅导致MT出现在肝细胞的细胞核和细胞质中，还出现在肝血窦和胆小管中。剖腹术后，MT免疫荧光仅在细胞质中观察到。目前的结果表明，MT可能参与细胞增殖和分化，以及这种金属结合蛋白的运输和分泌。
