Glutathione S-transferase in human endometrium: quantitation and interindividual variability in isoform content.

Objectives: The goals of the present study were to determine whether human endometrium contains glutathione S-transferases (GSTs), to identify the isoforms present (if any) and to assess the causes of any intersubject variability which was observed.

Method: Hysterectomy patients (n = 32, 13 with endometrial carcinoma) were examined in the core study. The ability of cytosol from these endometria to conjugate 1-chloro-2,4-dinitrobenzene was measured. Additional studies with chemical inhibitors and monoclonal antibodies to GSTpi were also performed.

Results: The pattern of inhibition caused by ethacrynic acid and cibacron blue strongly suggests substantial interindividual variability in type (alpha and pi dominant) and amount ( approximately 10-fold) of this important group of enzymes. Significantly lower GST activity was seen in cancer patients who were smokers when compared with all other subjects (p < 0.05).

Conclusion: There are substantial interindividual differences in the GST content of human endometrium. Furthermore, lower GST activity in tissues from endometrial carcinoma patients with a history of smoking may have contributed to the neoplastic transformation of this tissue.