Polymorphic expression of multidrug resistance mRNA in lung parenchyma of nonpregnant and pregnant rats: a comparison to cystic fibrosis mRNA expression.

Multidrug resistance (MDR1b) and cystic fibrosis transmembrane conductance regulator (CFTR) proteins are members of the "ATP-binding cassette" superfamily of transporters. They are associated with chloride channel activities and ATP secretion and have complementary patterns of expression in several organs. In the rat uterus, CFTR expression is replaced by MDR1b expression during pregnancy. We have studied whether expression of MDR1b and CFTR also vary in the lung during pregnancy. No variations in MDR1b or CFTR mRNA levels during pregnancy were detected. However, there was an unusual degree of variation in MDR1b mRNA expression in lung parenchyma between animals in both the control group and the pregnant group. If present among humans, polymorphic expression of MDR1 in lung parenchyma may explain part of the differences in lung symptomatology observed in the CF patients carrying the same mutation. Copyright 1997 Academic Press.