The adult pituitary contains a cell population displaying stem/progenitor cell and early embryonic characteristics.

A side population (SP) has been identified in a number of tissues, where it typically represents a small population enriched in stem/progenitor cells. In this study we show that the adult mouse anterior pituitary (AP) also contains a characteristic SP displaying verapamil-sensitive Hoechst dye efflux capacity. A majority of the SP cells express stem cell antigen 1 at a high level (Sca1high).