[The morphological characteristics of the pit cells in the rat liver after the use of the glycopeptide preparation Polyerga].

Pit cells are morphological equivalent of large granular lymphocytes with NK activity. The aim of our study is to define the morphological changes of pit cells in the liver of the rat after stimulation with the biological response modifier Polyerga. Polyerga was applied intramuscularly in a single dose of 6 mu g per kg body weight. The animals were perfused on the 24-th hour, 48-th hour, on the 4-th day and on the 7-th day after injection. The perfusion was done through the portal vein and the liver was processed for electron microscopical cytochemistry for endogeneous peroxidase demonstration. A 3-to-4-fold increase in the number of pit cells was observed within a period of 1 to 4 days after injection. Pit cell granules were negative for endogeneous peroxidase. After Polyerga stimulation pit cells showed a tendency of orientation of their organelles toward the contact area with Kupffer and endothelial cells. These changes are considered to represent the morphological expression of rat liver pit cell activation.