PERMEABILITY AND METABOLIC PROPERTIES OF A TROPHOBLAST CELL-LINE (HRP-1) DERIVED FROM NORMAL RAT PLACENTA

The HRP-1 cell line is derived from normal rat placenta and appears mo rphologically similar to and retains characteristic expression of cell ular markers of labyrinthine trophoblast cells. In this study, monolay ers of HRP-I cells grown on permeable supports mere evaluated as a pot ential in vitro system to study trophoblast transport and metabolism. The cell line was shown to express and retain functional activity of t he predominant placental cytochrome P450 isozyme, CYP1A1. Additionally , the HRP-1 cells retain functional activity of angiotensin I converti ng enzyme and carboxypeptidase N-like enzyme, peptidases characteristi c of the trophoblast. The permeation of several hydrophilic, inert mar kers across the HRP-I monolayers was observed to be dependent on effec tive molecular size and to be passive in nature. Functional asymmetry of the HRP-I cells was illustrated by the predominant permeation of li noleic acid in the apical-to-basolateral direction across the monolaye rs. Transferrin passage across HRP-I monolayers was concentration-depe ndent, was bidirectional, and could be inhibited by unlabeled transfer rin, features typical of the trophoblast transport system for transfer rin, Collectively, these properties suggest that the HRP-I cell line m ay provide a useful tool for evaluating some of the permeability and m etabolic properties of the trophoblast. (C) 1997 Academic Press.