Neuroendocrine hormones such as dopamine and insulin/insulin-like peptides play indispensable roles in growth regulation of animals, while the interplay between dopamine and insulin signaling pathways remains largely unknown in invertebrates. In the present study, we showed that tyrosine hydroxylase (TH), the rate-limiting enzyme of dopamine synthesis, was highly expressed in all tissues of the fast-growing oysters, and gradually increased with the development, which indicated the potential role of dopamine in growth regulation. Incubated with dopamine hydrochloride and insulin-like peptide recombinant proteins in vitro induced the expression of TH, suggesting a mutual regulatory relationship between insulin and dopamine signaling. Fasting and re-feeding experiments confirmed the role of TH in food intake regulation, also provide a clue about the potential regulatory relationship between the FoxO and TH. Further luciferase assay experiment confirmed that FoxO was involved in transcriptional regulation of TH gene through binding to its specific promoter region. This work provided insights into the crosstalk between dopamine and insulin signaling in growth control of mollusks.

多巴胺和胰岛素/胰岛素样肽等神经内分泌激素在动物的生长调节中发挥着不可或缺的作用，而多巴胺和胰岛素信号通路之间的相互作用在无脊椎动物中仍然很大程度上未知。在本研究中，我们发现酪氨酸羟化酶（TH）是多巴胺合成的限速酶，在快速生长的牡蛎的所有组织中均呈高表达，并随着发育逐渐增加，这表明了多巴胺的潜在作用。在生长调节。体外与盐酸多巴胺和胰岛素样肽重组蛋白孵育诱导TH的表达，表明胰岛素和多巴胺信号传导之间存在相互调节关系。禁食和再喂食实验证实了 TH 在食物摄入调节中的作用，也为 FoxO 和 TH 之间潜在的调节关系提供了线索。进一步的荧光素酶测定实验证实，FoxO通过与其特定启动子区域的结合参与了TH基因的转录调控。这项工作提供了对多巴胺和胰岛素信号在软体动物生长控制中的串扰的见解。