Immunochemical Studies of an Insulin-like Material in the Parotid Gland of Diabetic BB Rats

Immunocytochemical and radioimmunoassay studies were performed on pancreatic and parotid tissues from diabetic BB and control Wistar rats. Compared with those of normoglycemic controls, the pancreata of diabetic BB rats generally lacked insulin-containing Bcells. Extracts from the parotid glands of diabetic rats contained less immunoassayable insulin-like material than was present in parotid extracts of controls. However, the parotid glands of both groups of animals contained numerous cells displaying insulin-like immunoreactivity. These insulin-immunoreactive cells, located mainly in the intercalated portion of the duct system, were comparable to those we reported recently in the parotid glands of normal and streptozocin-diabetic Sprague-Dawley rats. The presence of an insulin-like material in the parotid salivary gland of two types of diabetic animals suggests that such cells may be spared, in part, from the effects of both chemical and hereditary diabetogenic factors.