SEASONAL VARIATIONS OF PCNA EXPRESSION IN PITUITARY OF ADULT MALE VISCACHA

ROSALES GABRIELA; FILIPPA VERÓNICA; MOHAMED FABIAN

Estancia Grande, San Luis.

Congreso; XXXII Reunión Científica Anual de Sociedad de Biología de Cuyo.; 2014

Sociedad de Biología de Cuyo

Some researchers have demonstrated that the cell population of anterior pituitary is not static but rather dynamic. The proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase-δ and it has been used for studying cell proliferation. PCNA is expressed mainly in the G1/S phase of cell cycle, decrease in G2 and is undetectable in metaphase. The aim of the present work was to localize and quantify the cells that express PCNA in pituitary pars distalis (PD) of adult male viscacha during summer and winter (long and short photoperiods, respectively). PCNA were detected by immunocytochemistry and morphometrically quantified by image analysis in pituitary PD. Labeled cells were counted and expressed as percentage of the total number of cells per microscopic field. The values were expressed as mean ± SEM and analysed by Wilcoxon test. PCNA-immunopositive cells were found isolated throughout the PD during both photoperiods. The immunostained nuclei were spherical though some nuclei were spindle-shaped or elongated. Some positive nuclei near follicular structures were irregular in shape. Mitotic figures in PD were infrequent. The percentage of PCNA cells during summer was significantly higher (p