Morphological aspects of glucagon and somatostatin islet cells in diabetic bio breeding and low-dose streptozocin-treated Wistar rats.

We noted discrepancies in the results of differing investigators studying the fate of pancreatic A and D cells in two apparently comparable diabetic animal models, namely spontaneous diabetes occurring in the Bio Breeding (BB) rat and that induced by multiple low-dose treatment with streptozocin. Our aim was twofold: (a) to clear up these inconsistences in order to evaluate whether these two experimental models are truly comparable; and (b) to add further results regarding the ultrastructural aspects of A and D cells after onset of diabetes. We therefore observed the postdiabetic ultrastructural changes involving the cell population of the islet of Langerhans using the above mentioned models. Results showed that: (a) in BB rats, A cells do not undergo significant changes whereas D cells numbers decrease significantly; (b) in the low-dose streptozocin-treated Wistar rats A cells do not undergo significant changes whereas D cell numbers increase. Our observations provide evidence that changes affecting D cells in "spontaneous" diabetes differ from those observed in the "induced" type.