Ultrastructure and histochemistry of the submandibular gland of the European hedgehog, Erinaceous europaeus L. I. Acinar secretory cells

Abstract

The ultrastructure and histochemistry of the submandibular gland of the European hedgehog was examined. The gland was of the mixed type, consisting of approximately equal numbers of mucous and serous cells. On the basis of staining reactions, it was concluded that the mucous droplets contained only one type of mucin, a periodate-reactive sialomucin, and that the serous granules contained glycoprotein. At the ultrastructural level, it was found that the mucous droplets often contained a dense spherule, and that their matrix was responsive to variations in fixation procedures. The serous granules developed in a remarkable fashion. Small, dense rodlets in Golgi-derived vacuoles became aligned to form a series of concentric dense shells. The intervals between shells became filled with small, dense particles. These particles, coupled with condensation of the granules, led to increasing densification of the granule matrix. The contents of mature serous granules were liberated by a merocrine process into the acinar lumen, where they disintegrated.