The change in pancreatic A- and B-cells in Chinese hamsters with spontaneous hereditary diabetes mellitus were investigated with specific immunohistochemical and image analyzing methods. A variety of pathological changes of the islets and change in number and distribution of the pancreatic A- and B-cells were found in diabetic Chinese hamsters. Microscopic examination revealed that the intensity of staining reaction of pancreatic B-cells varied greatly and the number of A-cells increased in this model. The results of image analysis showed that the range of the average optical density of B-cell staining was 54.4% wider than that in the control and the percentage of the glucagon positive immunoreactive area in the islet was significantly higher in diabetic Chinese hamsters(31.6?13.2%)than in the controls(21. 8?7.5%). These findings suggest that the islet cytology of this diabetic model changes significantly.

Pancreastatin, a novel peptide isolated from porcine pancreas, is capable of inhibiting the insulin release and the exocrine secretion of the pancreas. In this study, the localization and distribution of pancreastatin in guinea pig, pig and human pancreas were investigated with ABC immunostaining method combined with the glucose oxidase-DAB-nickle developing technique on paraffin sections. The results showed that in human pancreas pancreastatin-like immunoreactive(PLI)cells were mainly dist- ributed in the periphery of the islets. While in guinea pig and pig pancreas, the majority of islets cells showed positive pancreastatin immunostaining. The coexistence of pancreastatin and insulin in the pancreatic islets of guinea pig and pig were also proved with immunostaining of adjacent thin sections. PLI-cells were also found in the epithelium of the ducts and acini of all investigated pancreas. However, in the exocrine portion of human and pig pancreas, PLI-cells were present in amounts smaller than those found in guinea pig pancreas. The significance of the distribution pattern of pancreastatin was discussed.

The distribution of dopamine-immunoreactive endocrine cells and nerves in the digestive tract of guinea-pigs was examined with the ABC immunostaining technique. Dopamine-immunoreactive endocrine cells were observed in the pyloric antrum, small intestine and colon. The highest density of the positive ceils was found in the duodenum. From the jejunum to the colon the number of immunoreactive cells gradually decreased. A similar population of the positive cells was seen in the antrum and colon. Dopamine-immunoreactive nerve fibres were mainly located in the lamina propria and submucosa of the digestive tract. There were more positive fibres in the small intestine than in the stomach and colon. The dense networks of immunoreactive fibres were demonstrated in the villi. Some positive nerve fibres penetrated into the superficial and glandular epithelia. This representation indicated that the epithelial cells were directly innervated with the dopamine containing nerves.

The distribution of neuropeptide Yimmunoreactive (NPY-IR) fibers in the spleen of rat was investigated by using the immunohistochemical ABC method combine with glucose oxidase-DAB-nikel enhancement technique. The results demonstrated that the rat spleen is richly innervated by NPY-IR fibers. The NPY immunoreactive nerve fibers are mainly distributed along the branches of the arteries, especially surrounding the central arterioles. They are also observed in the connective tissue capsule, the lymphoid tissue of the white pulp, red pulp and marginal zone and around the splenic sinusoid. The positive fibers are closely related to the blood vessels and lymphocytes in the spleen, which suggested that these fibers may regulate the development and function of splenic lymphocytes. NPY may have a direct or an indirect effect on regulating blood circulation of the spleen and the lymphocytes.

In this study, the distribution of calcitonin gene-related peptide immunoreactive (CGRP-IR) nerve fibers in the spleen of the rat was investigated by using the immunohistochemical ABC method combined with glucose oxidase-DAB-nickel enhancement technique. The results showed that the rat spleen was richly innervated by CGRP-IR fibers. The nerve fibers containing CGRP were mainly distributed in the red pulp, especially surrounding the splenic sinusoid and small blood vessels. They were also observed in the lymphoid tissue of marginal zone, and occasionally in the periarterial lymphatic sheath (PALS). The positive fibers distributed in the spleen, which suggested that the fibers might modulate the development and function of splenic lymphocytes.

Dopamine is one of the bioactive amines which regulate many physiological functions. In order to study its localization and quantification in tissues with immunohistochemistry and radioimmunoassay, authors immunised New Zealand rabbits with dopamine-BSA (bovine serum albumin) complex and succeeded in the production of the specific antiserum. The antiserum was tested on routine paraffin sections of Bouin's fixed guinea-pig digestive tract with the ABC technique. The titre of the antiserum was 1:1000-1:2000. Results of substitution, absorption and cross-absorption tests proved that the positive staining obtained with the antiserum demonstrated the specific immunoreaction between the antibody to dopamine and the antigen in the tissues.