Ultrastructural characterization of epithelial cells of rabbit harderian gland with particular reference to their mode of secretion

The present study was carried out to shed some light on the ultrastructure of the rabbit Harderian gland in order to help determine its functions with particular reference to the mechanism of its secretion. Twelve adult male and female rabbits were used in this experiment. Small specimens from the Harderian glands were processed for light and transmission electron microscopic study. Obvious structural differences were not observed between male and finale rabbit Harderian glands. The rabbit Harderian gland appeared bibbed; the pink lobe and white lobe. The pink lobe was formed of simple cuboidal epithelial cells with very large lipid vacuoles while the white lobe was formed of simple cuboidal or columnar epithelium with small irregular lipid vacuoles. Lipid vacuoles could be seen in close contact with the plasma membrane at the luminal surface of the acinar cell to be secreted by merocrine mode of secretion. The apical parts of some cells appeared [is being extruded from the cellular apices towards the lumen to be secreted by apocrine mode of secretion. The white lobe contained intraluminal porphyrins accretions, whereas pink lobe lacks these accretion s. The Golgi complexes amid smooth endoplasmic reticulum were well developed in the cells of the white lobe than in those of the pink lobe. The epithelium of the excretory ducts was seen containing apical granules suggesting secretary activity. The glandular stroma possessed unmyelinated axons and capillaries. This study showed that there was no sexual dimorphism in rabbit Harderian: gland. The different mechanisms of secretions were essentially merocrine and an apocrine type, while the holocrine mode of secretion was unconfirmed. The rabbit Harderian gland might also have an endocrine function in addition to its exocrine function

Harderian gland of wistar rats revised as a protoporphyrin ix producer

In 1694 Johann Jacob Harder described, for the first time, the harderian gland, located near the eye in the great majority of vertebrates, and regarded it as a lacrimal gland. This gland has multiple functions that vary according to the animal species. In the present work, we review the literature on the harderian gland of rats, focusing our study on the detection of great amounts of protoporphyrin IX (PpIX) produced by rodent glands. Protoporphyrin IX is a powerful photosensitizer that is widely used for photodynamic therapy (PDT). We also discuss the anatomic and the histological evidence for the presence of PpIX in the harderian gland of Wistar rats. Protoporphyrin IX has been detected in the lumen and in acinar cells of this gland, as confirmed by fluorescence microscopy. These findings together with numerous reports in the literature suggest that the harderian gland could be useful experimental model for studying the photodynamic process.

The structure of the nasal chemosensory system in squamate reptiles. 2. Lubricatory capacity of the vomeronasal organ.

The vomeronasal organ is a poorly understood accessory olfactory organ, present in many tetrapods. In mammals, amphibians and lepidosaurian reptiles, it is an encapsulated structure with a central, fluid-filled lumen. The morphology of the lubricatory system of the vomeronasal organ (the source of this fluid) varies among classes, being either intrinsic (mammalian and caecilian amphibian vomeronasal glands) or extrinsic (anuran and urodele nasal glands). In the few squamate reptiles thus far examined, there are no submucosal vomeronasal glands. In this study, we examined the vomeronasal organs of several species of Australian squamates using histological, histochemical and ultrastructural techniques, with the goal of determining the morphology of the lubricatory system in the vomeronasal organ. Histochemically, the fluid within the vomeronasal organ of all squamates is mucoserous, though it is uncertain whether mucous and serous constituents constitute separate components. The vomeronasal organ produces few secretory granules intrinsically, implying an extrinsic source for the luminal fluid. Of three possible candidates, the Harderian gland is the most likely extrinsic source of this secretion.

As glândulas cefálicas de répteis e anfíbios brasileiros: III. estudo morfométrico da glândula de Harder de Lygophis Lineatus Dilepis Cope (1862) (Serpentes: Colubridae) / Cephalic glands of brazilian reptilia and amphibia: III. morphometric study of Harderian gland of Lygophis Lineatus Dilepis Cope (1862) (Serpentes: Colubridae)

Os autores estudaram morfológica e morfometricamente a glândula de Harder do Colubrídeo Lygophis Lineatus Dilepis. Baseados nos resultados os autores concluíram: 1) a glândula de Harder é do tipo túbulo-acinoso composto; 2) os ácinos dessa glândula säo constituídos por células sero-mucosas e os ductos por células mucosas; 3) foram avaliados morfometricamente a área acinar, o volume nuclear dos ácinos e ductos e a altura do epitélio dos ductos