Gestational N-hexane inhalation alters the expression of genes related to ovarian hormone production and DNA methylation states in adult female F1 rat offspring

• N-hexane inhalation during gestation changed the oestrus cycle in pups.
• Female hormone secretion from the granulosa was altered after maternal n-hexane inhalation during gestation.
• Star, Cyp11a1, Cyp17a1 and Hsd3b gene expression in the granulosa was altered after maternal gestational n-hexane inhalation.
• DNA methylation induced by prenatal n-hexane exposure may play a role in the regulation of female hormone genes.

Research has revealed that n-hexane can disrupt adult female endocrine functions; however, few reports have focused on endocrine changes in adult F1 females after maternal exposure during gestation. In this study, female Wistar rats inhaled 100, 500, 2500, or 12,500 ppm n-hexane for 4 h daily during their initial 20 gestational days. The F1 female offspring exhibited abnormal oestrus cycles. Compared with the controls, the in vitro-cultured ovarian granulosa cells of the 12,500 ppm group showed significantly reduced in vitro progesterone and oestradiol secretion. Elevated progesterone secretion was observed in the 500 ppm group, and decreased and significantly upregulated mRNA expression of the Star, Cyp11a1, Cyp17a1, and Hsd3b genes was observed in the 12,500 ppm and 500 ppm groups, respectively. The protein expression levels were consistent with the mRNA expression levels. Methylation screening of the promoter regions of these genes was performed using MeDIP-chip and confirmed by methylation-sensitive high-resolution melting (MS-HRM), and the observed methylation state changes of the promoter regions were correlated with the gene expression levels. The results suggest that the hormone levels in the female offspring after gestational n-hexane inhalation correspond to the expression levels and DNA methylation states of the hormone production genes.