Auto-paracrine regulation of the proliferation of pituitary ACTH-producing cells demonstrated by immunoblockade of IL-1Beta

ABSTRACT

Pituitary gland and is involved in the stimulationof ACTH secretion. However, to date ithas not been determined whether IL-1Beta is ableto regulate the proliferation of pituitaryACTH-producing cells, like other regulatoryfactors involved in the regulation of ACTHsuch as vasopressin or CRH. The aim of thepresent study was to address whether IL-1Beta isinvolved in regulating the proliferation andapoptosis of pituitary ACTH-secreting cells.Thus, we performed an in vitro study onmonolayer cultures of rat pituitary cells, neutralisingthe possible paracrine effect of IL-1Beta by immunoblockade of the interleukin andlater determining the degree of proliferationor apoptosis of ACTH-secreting cells. Theeffects of immunoblockade were validated bydetermining the modifications in the patternsof the immunohistochemical reaction toACTH-positive cells. Immunoblockade of IL-1Beta decreased the percentage and proliferationof ACTH-positive cells at all time-pointsanalysed, mainly between 6 and 12 h(p<0.01). Moreover, immunoblockade decreasedthe sizes of the cellular and nuclear areas atall time-points studied, with significantdecreases (p<0.01) after 3, 6 and 12 hours.The results obtained suggest that -in the sameway as it regulates the secretion of the hormone-IL-1Beta could be involved in regulating theproliferation of ACTH cells (AU)

RESUMEN

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