Effects of Arg-vasopressin and corticosterone on IL-1b-induced modifications of pituitary ACTH-producing cells

ABSTRACT

Interleukin 1b (IL-1b) stimulates the hypothalamic-pituitary-adrenal axis, however the autoparacrineeffects of IL-1b‚ on pituitary ACTHproducingcells and the relations among IL-1band Arg-vasopressin or corticosterone have notyet been analyzed. To address these effects,pituitary monolayer cultures were treated withIL-1b, Arg-vasopressin and corticosterone, eitheralone or in combined treatment, and animmunocytochemical, morphometric and densitometricstudy of ACTH-positive cells was carriedout. IL-1b significantly increased the percentageand cellular and nuclear size ofACTH-positive cells, and similar effects werefound following treatment with Arg-vasopressin.Combined treatment with IL-1b andArg-vasopressin increased these parametersmore than in separate treatments. Corticosteronedecreased these parameters and blockedthe effects of IL-1b and Arg-vasopressin in thecombined treatments. In sum, our results suggestthat IL-1b is an auto-paracrine regulator ofpituitary ACTH-producing cells, that it reinforcesthe stimulatory effects of Arg-vasopressinand that corticosterone is an inhibitory regulatorof the auto-paracrine effects of IL-1b and Argvasopressin (AU)

RESUMEN

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