Cell proliferation in pituitary of non-pregnant and pregnant viscachas.

ROSALES GABRIELA; PÉREZ EDITH; FILIPPA VERÓNICA; MOHAMED FABIAN

Ciudad autónoma de Buenos Aires

Congreso; XVIII Jornadas Anuales Multidisciplinarias. Sociedad Argentina de Biología; 2016

Sociedad Argentina de Biología

Proliferating cell nuclear antigen (PCNA) has been used to identify replicating cells in different tissues. Immunocytochemical staining patterns of PCNA have permitted the recognition of specific cell-cycle stages. In other species, it has been demonstrated that the number of pituitary cells increase during pregnancy and lactation. In viscacha, pregnancy lasts approximately 154 days, and three stages can be described: early (EP), mid (MP)-and late pregnancy (LP). The aim of this work was to analyze the expression of PCNA in pituitary pars distalis (PD) and pars tuberalis (PT) of non-pregnant (NP) and pregnant viscachas. Sixteen pituitaries (n=4, per group) were processed for light microscopy. PCNA immunoreactive (ir) cells were detected by immunocytochemistry and quantified by image analysis. In PT only nuclear labeling for PCNA was observed. The percentage of PCNA-ir cells increased during pregnancy compared with NP animals (NP: 0.46  0.04% vs. EP: 1.13  0.24%; MP: 0.90 0.10%; and LP: 1.14  0.09%; p0.05). In addition, the percentage of PCNA-ir cells was higher in PD compared with PT of NP animals. These results demonstrate and quantify the cell proliferation in pituitary PD and PT of female viscachas. The differences in the pattern of immunostaining for PCNA suggest that these cells are in different stages of cell-cycle. The increase of cell proliferation values during pregnancy might be relate to the increase of some pituitary cell populations, and with highest progesterone and androstenedione serum levels, as previously reported during the pregnancy of this rodent.