ASC SYSTEM ACTIVITY IS ALTERED BY DEVELOPMENT OF CELL POLARITY IN TROPHOBLAST FROM HUMAN PLACENTA

被引:42
作者
FURESZ, TC
SMITH, CH
MOE, AJ
机构
[1] WASHINGTON UNIV,ST LOUIS CHILDRENS HOSP,SCH MED,EDWARD MALLINCKRODT DEPT PEDIAT,1 CHILDRENS PL,ST LOUIS,MO 63110
[2] WASHINGTON UNIV,ST LOUIS CHILDRENS HOSP,SCH MED,DEPT PATHOL,ST LOUIS,MO 63110
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1993年 / 265卷 / 01期
关键词
ALANINE TRANSPORT; NEUTRAL AMINO ACID TRANSPORT; EPITHELIAL TRANSPORT; CELL DIFFERENTIATION;
D O I
10.1152/ajpcell.1993.265.1.C212
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
Pathways of neutral amino acid uptake were investigated in vitro during differentiation of primary cultures of trophoblast isolated from full-term human placentas and a clone (b30) of the BeWo cell line. Inhibition of initial alanine (0.1 muM) uptake by 2-(methylamino)isobutyric acid and unlabeled alanine revealed two Na+-dependent systems and one Na+-independent transporter. Characterization of these transporters, by selective inhibition, suggested system A, ASC, and L-like transporters. Concomitant with formation of microvillous membrane and syncytium, system ASC activity decreased from 16.1 +/- 2.8 pmol . mg DNA-1 . min-1 at 24 h to 2.4 +/- 1.1 pmol . mg DNA-1 . min-1 at 72 h. Na+-independent alanine uptake increased from 6.0 +/- 2.0 to 12.9 +/- 0.9 pmol - mg DNA-1 . min-1 at 24 and 72 h; respectively. Similarly, alpha-(methylamino)isobutyric acid-insensitive, Na+-dependent activity in b30 cells (100 muM alanine) decreased from 6.5 +/- 1.6 to 1.2 +/- 1.2 nmol . mg DNA-1 . min-1 for control and forskolin-treated cells, respectively. We conclude that membrane specialization accompanying fusion and differentiation of the cytotrophoblast to form syncytiotrophoblast results in a polarization of neutral amino acid transport systems.
引用
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页码:C212 / C217
页数:6
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