[Morphometric analysis of lymphoid organs in the hypophysectomized rat].

The effects of hypophysectomy on the lymphoid organs were evaluated in Wistar rats by morphometrical analysis: after 30 days the percentage of thymus cortical area and lymph node paracortical areas were reduced. In the thymus cortex, signs of orthological involution (e.c.: nodular cortex) appeared. A significant enlargement of lymph node cortical areas, containing a high number of germinal centers with degenerative changes, could be seen. These findings suggest a significant trophic action of hypophysis on thymus and, perhaps, an impaired lymph node antibody mediated response due to the loss of T-B cooperation.