Studies on streptozotocin diabetes

Spontaneous recovery from streptozotocin-induced diabetes in rats pretreated with pertussis vaccine or hydrocortisone

Following the intravenous injection of streptozotocin into rats, postprandial hyperglycaemia was sustained from 24 hours over a subsequent period of some weeks and the rats were glucose intolerant. When streptozotocin was similarly injected into pertussis-sensitized or hydrocortisone treated rats, the postprandial hyperglycaemia observed at 24 hours did not persist, but showed a progressive decline until near normoglycaemia was obtained a week later. These animals manifested normal glucose tolerance one week after streptozotocin. Thus, a spontaneous recovery from streptozotocin-induced diabetes occurred under these conditions. This spontaneous recovery from diabetes was associated with hyperinsulinaemia in the fed state.

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.