Different Populations of Pinealocytes in the Pineal Gland of the Mole-rat (Spalax leucodon, Nordmann)

Abstract

This chapter focuses on different populations of pinealocytes in the pineal gland of the mole-rat (Spalax leucodon, Nordmann). The ultrastructural characteristics of the cells, combined with light-microscopic findings, suggest the existence of different populations of pinealocytes. The accumulations of granular endoplasmic reticulum and mitochondria in some cells, the abundance of large vacuoles and cisternae of endoplasmic reticulum in others, the presence of crystalloid contents within the perinuclear space in a third type of cells, and the presence of pinealocytes with large granules in a fourth, all particular cytologic characteristics in the process of protein synthesis, speak in favor of the presence of cells with different physiological characteristics. The cells containing accumulations of lipid droplets can be identified with those which were characterized by the presence of PAS-positive granules. This would indicate the presence of a glycolipid product in a certain type of pinealocytes. The results described here partially agree with the studies on Spalax ehrenbergi Nehring . They are in favor of a multihormonal function of the pineal gland, in agreement with the opinion of some other authors.