Developmental regulation of glutathione S-transferases.

1. cDNA probes for individual isoenzymes of rat glutathione S-transferases were used to determine steady state levels of their mRNAs in liver and brain during development. 2. Foetal livers were enriched in Yp transcripts (that are characteristic of hyperplastic nodules and hepatocellular carcinomas), but these forms decreased after the first week of postnatal development and were not detected in adult livers. In contrast, in adult brains Yp levels increased. 3. Ya forms that were present at low levels in foetal and neonatal livers, increased markedly during development. Ya was not detected in brain. 4. The Yb1 and Yb2 GSTs were present in higher amounts than Ya in foetal livers, and these isoenzymes also increased in adults.