Genetic polymorphisms of glutathione S-transferase T1 (GSTT1) and alterations of sex hormones in filling-station workers

Objective

To determine the health effects of gasoline exposure as measured by levels of sex hormones (total testosterone, follicle-stimulating hormone [FSH], and luteinizing hormone [LH]) of male filling-station workers.

Design

Case-control study.

Setting

Filling stations in Shiraz (Fars province, Iran).

Patient(s)

One hundred fourteen male gasoline workers and 112 age-matched (±5 years) and sex-matched controls with no occupational exposure to gasoline.

Intervention(s)

None.

Main Outcome Measure(s)

Serum levels of testosterone, FSH, and LH, and expression of the GSTT1 genotype.

Result(s)

All hormone measurements were in the normal range although subclinical changes were detected in some indexes. Men exposed to petrochemicals had lower mean serum testosterone levels compared with unexposed men, regardless of the presence of the GSTT1 genotype. However, this decrease (expressed as mean ± standard deviation) is most pronounced in the group possessing the GSTT1-null genotype (4.26 ± 1.44 ng/mL vs. 5.48 ± 0.98 ng/mL) compared with the group possessing the GSTT1 genotype (4.23 ± 1.73 ng/mL vs. 4.67 ± 1.21 ng/mL). The LH levels varied between the two groups; the mean serum LH was lower in the exposed versus unexposed men who possessed the GSTT1 genotype (2.82 ± 1.32 IU/L vs. 3.20 ± 1.17 IU/L) and higher in the exposed versus unexposed men who possessed the GSTT1-null genotype (3.52 ± 1.37 IU/L vs. 2.76 ± 1.07 IU/L).

Conclusion(s)

Testosterone levels were statistically significantly decreased in male gasoline workers compared with men who had had no occupational exposure to gasoline. The relevance of the GSTT1 genotype to these differences remains to be determined.

Key Words: Occupational exposure, sex hormones, gasoline, polymorphism, GSTT1