The development of gamma-glutamyltransferase in a pig renal-epithelial-cell line in vitro. Relationship to amino acid transport.

The pig kidney-cell line, LLC-PK1, possesses gamma-glutamyltransferase with properties similar to those of the purified renal enzyme. gamma-Glutamyltransferase activity increases after cells are seeded at low density to reach values comparable with those found in kidney cortex when the cells are fully confluent. This increase is paralleled by an increase in alpha-methyl D-glucoside uptake. In contrast, the uptakes of L-leucine and L-alanine decrease during this time. These results suggest that gamma-glutamyltransferase is not important as a mediator of the renal transport of neutral amino acids.