Thyroid hormone metabolism and excretion
I have partially answered this question by discovering that the metabolic pathway is called enterohepatic circulation. In this interaction bile salts are absorbed and transported out of ileal mucosal cells by binding to albumin.

However, it is still unkown to me exactly how it is that thyroxine and other hormones are moderated in this process and how it works. Does the albumin collect thyroxine as well as bile salts? How is the process moderated? In other words, bile salts are allowed to be excreted according to some moderated control mechanism. What is this mechanism?