The impact of n-hexane on the secretion of mouse estrogen and progesterone

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) <i>In vivo</i> 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) <i>In vitro</i> 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. <i>In vivo</i> 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). <i>In vitro</i>, 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). <i>In vitro</i>, 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.