Thyroid hormone regulation of rat pituitary tumor cell growth: a new role for apotransferrin as an autocrine thyromedin

Abstract

In the 40 years of transferrin research, no previous role for apotransferrin has been recognized other than to serve as a plasma carrier for dietary and storage iron. Our studies have revealed a new 'autocrine' growth role for this molecule as well as a possible new cell-cell bridge/CAM function. Certainly, these observations have opened many new areas of investigation both with regard to thyroid hormone action and the function of apotransferrin. In addition, there is now accessible the broader question of tissues other than pituitary which might utilize apotransferrin to regulate responsiveness to thyroid hormones.