CONICET | Buscador de Institutos y Recursos Humanos

ABSTRACTThe viscacha is a seasonal rodent that exhibit an annual reproductivecycle with periods of maximum reproductive activity and gonadalregression. We studied seasonal variations in the morphologyand cellular population of the seminal vesicles (SVs) during both periodsand in impuber animals. Seminal vesicles were studied by lightand electronic microscopy. Measurements of epithelial height, nucleardiameter, luminal diameter, and muscular layer were performed. Also,we studied the distribution of androgen receptors (AR) in this glandduring the reproductive cycle and in impuber animal. During gonadalregression, principal and clear cells showed signs of reduced functionalactivity. These were characterized by an epithelium of smallerheight, irregular nuclei, and cytoplasm with few organelles, dilatedcisterns, and glycogen granules. In impuber animals, the principalcells showed large nuclei with chromatin lax and cytoplasm withsmall mitochondria, poorly developed Golgi apparatus, and granulesof glycogen. On the other hand, the cells exhibited seasonal variationsin the distribution and percentage of immunolabeled cells to ARthroughout the annual reproductive cycle. During the gonadal regressionperiod, glandular mucosa exhibited numerous epithelial cellswith intense nuclear staining. However, fibromuscular stromal cellswere weakly positive for AR in contrast to what was observed duringthe activity period. Considering that testosterone values are lower inadult animals during the period of gonadal regression and in impuberanimals, our immunohistochemical results show a significant correlationwith the percentage of AR-immunopositive cells. In conclusion,these results demonstrate that the structure of the SVs changes inthe activity period of viscacha, probably because of elevated levels of testosterone leading to an increase in the secretory activity of epithelialcells.