The results indicate that diabetes affects submandibular gland structure even when glandular function appears unaltered and suggest that morphological changes reflect functional changes chiefly regarding the secretory activity.

The hormone melatonin influences oral health through a variety of actions, such as anti-inflammatory, antioxidant, immunomodulatory and antitumour. Many of these melatonin functions are mediated by a family of membrane receptors expressed in the oral epithelium and salivary glands. Using immunoblotting and immunohistochemistry, recent studies have shown that the melatonin membrane receptors, MT1 and MT2, are present in rat and human salivary glands. To date, no investigation has dealt with the ultrastructural distribution of the melatonin receptors. This was the aim of the present study, using the immunogold method applied to the human parotid gland. Reactivity to MT1 and, with less intensity, to MT2 appeared in the secretory granules of acinar cells and in the cytoplasmic vesicles of both acinar and ductal cells. Plasma membranes were also stained, albeit slightly. The peculiar intracytoplasmic distribution of these receptors may indicate that there is an uptake/transport system for melatonin from the circulation into the saliva.

The epithelium of the human ampulla consists of rare basal cells and a single type of principal (secretory) cells. The principal cells, which vary in height from cuboidal to columnar, often have conical or club shaped apical portions projecting and bulging into the lumen. Their cytoplasm contains an abundant rough-surfaced endoplasmic reticulum, numerous mitochondria, and many lipopigment granules. The Golgi apparatus is well developed and originates the secretory vacuoles which are discharged by exocytosis. Though the majority of nuclei are ovoid, deeply fissured or even lobated nuclei are not uncommon. The basal cells are smal,', nonsecretory cells, whose cytoplasm shows numerous filaments having a diameter of 55 A. The lumen contains masses of amorphous secretions and some spermatozoa. The human ampulla is a gland endowed with the same morphological features as those of the seminal vesicles.

Oral Diseases (2011) 17, 217–220 Background and Objectives:  Statherin is a salivary protein involved in the formation of enamel pellicle and in regulation of calcium homeostasis. Diabetes and other pathologies affect both salivary flow and protein secretion by salivary glands, causing increased susceptibility to mucosal infections, tooth demineralization, and caries. The purpose of this study was to compare the statherin expression in submandibular glands of healthy and diabetic subjects. Materials and Methods:  Fragments of submandibular glands obtained from diabetic and non diabetic patients were fixed, dehydrated, embedded in Epon Resin and processed for the immunogold histochemistry. The results were statistically evaluated. Results:  Specific statherin labeling was demonstrated in secretory granules of acinar cells in both diabetic and normal samples. The staining was much more intense in the latter compared to those of diabetics. The labeling density was quantified by evaluating the number and spatial distribution of gold particles within the granules. The number of gold particles was significantly lower in glands from diabetics than in control glands. Conclusions:  The results obtained suggest that a reduced statherin secretion by salivary glands might be partly responsible for a less effective protection of the oral tissues, resulting in an higher incidence of caries and oral infections associated with diabetes.

Gene expression and cell localization of the neuroendocrine protein VGF were studied in the rat anterior pituitary. In females, four antisera against nonoverlapping regions of VGF immunostained a small number of lactotropes and many gonadotropes. In the latter cells, VGF immunoreactivity was localized to a subpopulation of secretory granules. Distinct changes were seen after estrus, with a significant increase in VGF messenger RNA (whole pituitary), whereas VGF immunostaining was strikingly reduced in gonadotropes and somewhat more abundant in lactotropes. In male rats, gene expression was low, and immunoreactivity was restricted to a few lactotropes. After castration or ovariectomy, VGF messenger RNA was high, and VGF immunoreactivity was abundant in gonadotropes. Selective localization and cyclic modulation suggest involvement of the VGF gene product(s) in pituitary gonadotrope and/or lactotrope function.