Parotid Gland Function in Streptozotocin-diabetic Rats

Abstract

The in vivo response of parotid glands to adrenergic, cholinergic, and peptidergic agonists was studied in control, streptozotocin- (one month's duration), and insulin-treated (three hr) diabetic rats. Neither diabetes nor insulin had an effect on the response to physalaemin. In contrast, physalaemin threshold-dose was lower and maximal response greater in control rats placed on a bulk diet. As previously described, diabetes resulted in nonparallel changes in parotid protein composition, including a production in amylase and an increase in peroxidase concentrations (mg/mg protein). In contrast to the results observed with physalaemin, response to methacholine was significantly reduced in diabetic animals, and could be restored to control levels by insulin. Placement of animals on a bulk-diet, however, had no effect on threshold response to methacholine. Finally, response threshold for epinephrine was unaffected by diabetes, insulin, or bulk diet. Thus, insulin appears, directly and specifically, to alter the response of parotid acinar cells to cholinergic stimulation.

Lowered Susceptibility of Muscarinic Receptor Involved in Salivary Secretion of Streptozotocin-Induced Diabetic Rats

“…7, STZ rats showed slight fatty degenerative changes in parotid glands of the STZ-rat, otherwise minimal changes with vacuolation in the submandibular glands. Our results obtained under the relatively initial diabetic conditions were consistent with the previous reports observed under advanced diabetic conditions (13,15,32). The findings such as a lipid accumulation, a decrease in amylase release, and an increase in acetylcholinesterase activity are found in the salivary glands, especially parotid glands of the initial diabetic rats (13,22,23,33).…”

“…However, water-restriction induced a remarkable decrease in salivary secretion of the STZ rats compared with the control. On the other hand, pilocarpine-stimulated whole saliva secretion was remarkably decreased in STZ rats, compared to the control rats, as well as those reported by other investigators (15,23,24). The volume of saliva elicited by the parotid gland was also decreased after stimulation of pilocarpine and its level was about 30% of the control level (Fig.…”

“…1). Some investigations clarified that the insulin administration to STZ rat was very effective for recovering secretory dysfunction (12,15,21,32), histological degeneration (12,21), and fatty accumulation (34) in the salivary gland. Our findings also supported their results and indicated that a decrease of salivary secretion was induced by diabetic mellitus, but not a direct action of STZ.…”

Expression of BMP7 is associated with resistance to diabetic stress: Comparison among mouse salivary glands

“…Secretion in the submandibular gland also decreased, but to a lesser degree than that in parotid gland. Our results are consistent with those of other studies on streptozotocin-induced diabetes (Hand and Weiss, 1984;Anderson, 1987;Kimura et al, 1996;Watanabe et al, 2001). …”

Stereology and ultrastructure of the salivary glands of diabetic Nod mice submitted to long‐term insulin treatment

“…However, the authors did not characterize both functional and morphological recovery of the glands (Anderson and Shapiro, 1980;Watanabe et al, 2001). Also, no significant recovery of parotid gland weight was observed in other studies administering a single dose of insulin to chemically induced diabetic rats (Anderson, 1987;Pinkstaff, 1996). Similarly, another experiment conducted on diabetic rats submitted to insulin replacement for 7 days failed to characterize the morphological and functional restructuring of the parotid and submandibular glands (Anderson, 1983;Chan et al, 1993).…”