Immunohistochemical and ultrastructural study of pituitary folliculostellate cells during aging in rats

The impact of aging on pituitary folliculostellate (FS) cells is not well k nown. The aim of the work reported here was to carry out a quantitative imm unohistochemical assessment of the FS population in male and female rats du ring aging and to correlate the findings with possible changes at the ultra structural level. Young (4 months), old (20 months) and senescent (29 month s) Sprague-Dawley rats of both sexes were sacrificed by rapid decapitation, their pituitaries dissected a nd processed by both light immunohistochemis try and electron microscopy. Serial sections (4 mu m) were obtained at diff erent levels and immunostained by mea ns of rabbit anti-S100 serum as the p rimary antibody and a peroxidase-mediated EnVision System (Dako). Measureme nt of volume density (VD) and cell density (CD) was made in S100-reacting e lements by means of an image analysis system (Imaging Technology, Optimas). These parameters were found to be significantly (p < 0.05) decreased in ol d and senescent rats as compared to young animals. In senescent females, wh ich presented a high incidence of microprolactinomas, a significant (p < 0. 01) increment of VD a nd CD was observed in FS cells in the area surroundin g the adenomas, together with a marked decrease in those parameters with in the tumors. Sexual dimorphism was not found except for the prolactinoma-be aring female group. The ultrastructure of FS eel Is showed the typical char acteristics previously described in the pituitary gland. Only moderate chan ges in the endoplasmic reticulum were observed in old and senescent animals . We conclude that aging has a clear effect on the morphology of the pituit ary FS cell population. Copyright(C)2000S;KargerAG.Basel.