ABSTRACT
Aim: To study the toxic effect of n-hexane on sex hormone levels, including its effect on ovarian sex hormone secretion levels and the underlying mechanism. 1) In vivo experiment: The mice were exposed to n- hexane by static inhalation of doses of 0, 3.0, 15.1 or 75.8 ml/m3 once a day (4 hours), 7 days a week, for 5 consecutive weeks. After exposure, mouse sera were sampled to measure estradiol (E2) and progesterone (P4) levels by electrochemiluminescence immunoassays (ECLIA). 2) In vitro experiment: mice at different stages of the estrous cycle were sacrificed and their minced tissue pieces were incubated in medium containing hexane-2,5-dione (2,5-HD). Then, the E2 and P4 levels in the media were measured by ECLIA. In vivo assays, the serum P4 levels in each group were lower than the control group, which was statistically significant (F = 6.196, P < 0.01). In the minced ovary tissue culture medium, the E2 level of 75.8 mL/m3 dosage group was decreased (96.9522 ± 7.8652)) compared to the control group (119.1600 ± 25.6420), with statistical significance (P < 0.01). The P4 levels of 15.1 mL/m3 and 75.8 mL/m3 dosage groups were also decreased (18.5938 ± 12.485pmol/L, 13.5550 ± 5.7789 pmol/L) and were statistically significantly (F = 6.196, P < 0.01) lower than that of the control group (45.2213 ± 16.5393 pmol/L). In vitro, the E2 levels at various stages of the estrous cycle were significantly different from the control groups (P < 0.05). Moreover, there was an interaction between the two variables (P < 0.05). In vitro, different concentrations of 2, 5-HD significantly inhibited the P4 level (P < 0.05). The P4 levels at various stages of the estrous cycle were also significantly different from controls (P < 0.05), with no interaction (P > 0.05). The results indicate that n-hexane may inhibit release of ovarian E2 and P4, which may be the main reason for the interference of the reproductive endocrine system by n-hexane.