Progesterone (P4) is an extensively applied progestin in human and veterinary medicine that has been widely detected in ambient aquatic environments, which can be detrimental to the health of aquatic organisms. Here we investigate the long-term effects of P4 on the transcription of genes related to the circadian rhythm signaling pathway and hypothalamic-pituitary-gonadal (HPG) axes in the crucian carp, which may have a potentially negative on endocrine-disrupting and sex differentiation impacts. Our results suggest that the expression of genes associated with the circadian rhythm signaling pathway are altered following exposure for 10, 20, 30, 40, 50 and 60 d, leading to disorders in the endocrine system disorders and the regulation of HPG axes-related gene expression. These maladies may affect gonadal development and the reproductive systems of crucian carp and provide a plausible mechanism for the observed change in sex ratio toward females after 180 d.

孕酮（P4）是在人和兽药中广泛应用的孕激素，已在周围水生环境中被广泛检测到，这可能对水生生物的健康有害。在这里，我们调查P对鲤鱼中昼夜节律信号转导通路和下丘脑-垂体-性腺（HPG）轴相关基因的转录的长期影响，这可能会对内分泌干扰和性别分化产生负面影响影响。我们的结果表明，与生物钟节律信号通路相关的基因表达在暴露10、20、30、40、50和60 d后发生改变，从而导致内分泌系统疾病和HPG轴相关基因的调节表达。