Regulation of the GST Mu-1 isoenzyme in Y1 cells by adrenocorticotropic hormone is primarily transcriptional.

Abstract

In earlier experiments, adrenocorticotropic hormone (ACTH) was shown to decrease the level of glutathione transferase M1 (murine glutathione transferase mu-1) (mGSTM1), as well as of the corresponding mRNA, in a murine adrenocortical cell line. In the present study, the effect of ACTH on mGSTM1 gene transcription was examined using two techniques. First, a cDNA that coded for the mGSTM1 subunit but lacked the corresponding promoter sequences was transfected into the adrenocortical cell line, and the effect of ACTH on the level of the corresponding transcript was compared to that of endogenous mGSTM1 mRNA. The other technique used was nuclear run-on transcription, where the rate of transcription of endogenous mGSTM1 mRNA in ACTH-treated cells was compared to that in untreated control cells. These experimental approaches indicated that the rate of transcription of the mGSTM1 gene is regulated by ACTH in adrenocortical cells.