Endocrine-cell populations in the islets of Langerhans of mutant mice with a severe hypoinsulinemic diabetes (obiob or dbldb on the C57BL/KsJ background) or with a mild hyperinsulinemic diabetes (ob/ob or db/db on the C57BL/6J background) were studied quantitatively by immunofluorescence and morphometry. In severely diabetic mice, islets presented a reduced proportion of insulin-containing cells buf increased glucagon-, somatostatin-, and pancreatic polypeptide (PP)-containing cells, as compared with islets of control (+/+) mice. An inverse change was observed in islets of mildly diabetic mice: islets were hypertrophie and composed mostly of insulin-containing cells, with decreased proportions of glucagon-, somatostatin-, and PP-containing cells.

In both types of diabetic syndromes, the changes in cell populations induced a qualitative alteration of cellular interrelationships in the affected islets.