Characterization of GFAP expression and cell proliferation in the rat median eminence following hypophysectomy

• Vázquez, R. ^[1] ; Blanco, E. ^[1] ; Sánchez, F. ^[1] ; Juanes, J. A. ^[1] ; Rubio, M. ^[1] ; Santos, M. ^[1] ; Vázquez, G. ^[1] ; Hernández, E. ^[1] ; Riesco, J. M. ^[1] ; Carretero, J. ^[1]
  1. [1] Universidad de Salamanca

     Universidad de Salamanca

     Salamanca, España

     
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 16, Nº. 4, 2001, págs. 1107-1116
• Idioma: inglés
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• Resumen

  • To analyze whether the reorganization of the rat median eminence after hypo physecto my might be re la ted to cha nges in glia l fibrilla ry acidic pro te in (GFAP)-and ce llular proliferation, the distributio n of cells immunoreactive fo r GFAP and the proliferation rate of such cells were analyzed at 20, 40 and 60 days post-hypophysecto my. For this study, fo ur rost ra -cauda l regions of the median eminence were differentiated: the re trochiasmatic, p reinfundibula r, infundibul a r a nd postinfundibular r egions. In each of these regio ns, three layers were studied: the ependymal, the internal and the external. A t 20 and 40 days afte r hypo physecto my, significant increases in ce llular proliferation affecting all three layers studie d in th e preinfundib ul a r a nd infund ibula r regio ns were found. At th e sa me time po ints, in c reases in G FA P expressio n were also observed. However, afte r 60 days, GFAP a nd proliferative ce llular nuclea r antigen (PCNA) expression decreased . Altho ug h variatio ns of PC NA a nd GFAP leve ls were evident, no colocalisatio n of PC NA and GFAP was found in the cells of the median eminence in untreated o r hypophysec tomized rats when sections were analyzed by double immunohistochemica l staining. Our results suggest that reorganizatio n of median eminence in volves a lt e r a ti o ns (or modula ti o n) of GFAP-immuno reactive cells togethe r with a pro life ratio n of cells that are not GFAP-immuno reactive. This study also demonstrates that this reorganizatio n is completed within the first t wo months after hypophysectomy.