[Salivary peptide P-C (III). Its relation to the pathogenesis of diabetes mellitus]

Previous immunohistochemical study showed that salivary peptide P-C like immunoreactivity, originally isolated from whole human saliva, was present not only in human salivary glands but also in human pancreatic B-cells. To elucidate the pathophysiological role of this peptide-like immunoreactivity in human pancreatic B-cells, immunohistochemical study using antisera against both insulin and peptide P-C was carried out on the paraffin embedded pancreatic tissues of 27 diabetic patients and 30 control subjects. Positive immunofluorescence due to insulin was detected in 96% of the diabetic pancreases and 100% of the controls. A pancreas of only one IDDM did not have any immunofluorescence due to insulin. Thus, no significant differences were seen in connection with the presence of insulin between pancreases of NIDDM and the controls, though the present study did not examine whether the number of pancreatic B-cells in the pancreas of NIDDM was the same as that in the controls or not. In contrast, positive immunofluorescence due to peptide P-C like immunoreactivity was demonstrated in only 41% of the diabetic pancreases but in 87% of the controls. In view of the fact that the diabetic pancreases and the controls were fixed and embedded into paraffin in the same department of pathology and under the same conditions, the negative finding for salivary peptide P-C like immunoreactive in the diabetic pancreas seems to result neither from the effects of fixatives nor the destructive postmortem effects of enzymes on the antigenicity of peptide P-C like immunoreactivity but from the decreased content of peptide P-C like immunoreactivity in the diabetic pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)