[Hepatic caecum of amphioxus and origin of vertebrate liver].

Previous studies on morphology and embryology revealed that the Hatschek's pit, endostyle and hepatic caecum in amphioxus were homologous to the precursors of pituitary, thyroid and liver in vertebrates, respectively. Here, we summarize the recent advances on the relationship between amphioxus hepatic caecum and the vertebrate liver as well as the origin of growth hormone/insulin-like growth factor (GH/IGF) and thyroid hormone/thyroid hormone receptor (TH/THR) signal pathways, which will provide molecular support to the homology of amphioxus hepatic caecum to vertebrate liver.