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 GST pi were also performed. Results: The pattern of inhibition caused by ethacrynic acid and cibacron blue strongly suggests substantial interindividual variability in type (a and n dominant) and amount (similar to 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.