Influence of tobacco smoking on metallothionein isoforms contents in human placenta, amniotic fluid and milk.

SDS-PAGE was used for separation of heat-stable proteins in placenta, amniotic fluid and milk of women who smoke actively and those exposed to tobacco smoke (passive smokers). In the number of protein bands stained with Coomassie brilliant blue R-250, several bands were stained with silver nitrate. The presence of low-molecular band with molecular weight of 6.5 kDa, corresponding to the mobility of electrophoretic MT-1 was detected in placenta, amniotic fluid and milk. The involvement of MT-2 isoform was much lower, although more evident in amniotic fluid and milk of active smokers. In this group of women an enhanced concentration of the band with molecular weight of 25-30 kDa was observed in placenta, colostrum and milk on the second day after delivery; several protein bands emerged in the area of the same mobility in amniotic fluid; the presence of the band with molecular weight of 12.5 kDa and the absence of protein bands of 25-30 kDa were found in milk excreted on the third day post partum. Our results show the apparent differences between proteingrams of placenta, amniotic fluid and milk of active and passive smokers.