Modification of streptozotocin-induced diabetes in rats by pretreatment with cortisone.

Cortisone pretreatment considerably enhances the mortality of young, male, streptozotocin-injected Holtzman rats. In those that survive, cortisone pretreatment decreases the ensuing hyperglycaemia, extends the period during which streptozotocin-induced B cell damage can be observed from less than two to as much as four to seven days and permits the persistence of poorly granulated B cells in such animals. These effects are at least partially attributable to a cortisone-induced augmentation of the total B cell mass. Compared with the high degree of protection against alloxan-induced damage afforded the pancreatic B cells of cortisone-pretreated rabbits, the protective effect of cortisone against B cell destruction in streptozotocin-injected rats is thus much more limited in scope. Species differences as well as differing pathogenetic mechanisms may account for these results.