Adult Pituitary Stem Cells

Stem cells were first identified in adult organs with high regenerative capacity including skin, liver, intestine and bone marrow. The pituitary gland is an organ with low cell turnover, and while differentiated cells can re-enter the cell cycle, most hormone producing cells are not dividing. The adult pituitary gland has some capacity to regenerate after tissue injury. Recent studies have reported potential populations of stem cells in the pituitary. Stem cells population belongs to the chromophobe/folliculo-stellate population of adenohypophysis. Studies to date suggest that at least a part of the endocrine cells originates from marginal layer adjacent to Rathke’s cleft. Different groups, using diverse approaches, have demonstrated the presence in the pituitary of cells with progenitor or stem cell capacities and have characterized the pituitary stem cells, progenitors, and transit amplifying cells. A large variety of markers used to identify pituitary progenitors and stem cells make the integrated view difficult over the results obtained. Until now the nature of pituitary stem cells remains a matter of debate, and additional studies are needed to define the progenitors and stem cells in adenohypophysis.

Keywords: Adenohypophysis, Folliculo-stellate cells, Markers of stem cells, Progenitor/stem.