Figure 1.

Possible mechanisms underlying remodeling of the pituitary cell landscape. Pituitary remodeling during postnatal (patho-)physiological processes may involve differentiated endocrine cells that either proliferate (as, for instance, observed in the neonatal growth wave) or transdifferentiate (as, for instance, seen during puberty). In addition, the stem cell compartment may become activated (involving increased proliferation and upregulated stemness factors and signaling pathways) as, for instance, observed following pituitary injury. Pituitary stem cells, activated or not, may contribute to new endocrine cell formation during the pituitary remodeling events through differentiation (as, for instance, after target organ removal such as adrenalectomy) and/or through sending paracrine signals to surrounding cells (as, for instance, likely to occur during tumorigenesis). AP, anterior pituitary; PP, posterior pituitary, IL, intermediate lobe.