Responses of pancreatic b cells to alloxan and streptozotocin in the guinea pig.
Guinea pigs injected with streptozotocin were significantly hyperglycemic on day 1 after injection but only mildly so on day 14. However, serum insulin levels were significantly depressed on day 14; at this time the animals had lost 25% of their initial body weights and were severely glycosuric. The volume fraction of immunostainable B cells in the pancreas was reduced to one third of control values by day 1 after injection and remained at this level by day 14. Animals that received alloxan were slightly hyperglycemic on day 1 but not day 14. Both serum insulin and volume fraction of B cells in the pancreas were reduced by 70% on day 1 but had returned to control levels by day 14. Body weights for this group were equivalent to controls at both time points. These data indicate that: streptozotocin treatment of guinea pigs causes a diabetes-like condition characterized by insulin deficiency, pancreatic B cell loss, glycosuria, and weight loss, which are not reversed in the first 2 weeks after injection, whereas hyperglycemia is only transitory; alloxan also produces a diabetes-like condition early after injection, but all signs of diabetes disappear within 2 weeks, by which time serum insulin levels and the volume fraction of B cells in the pancreas have returned to normal. The experimental results suggest that regeneration of islet B cells following destruction by alloxan may be the primary cause of the recovery of alloxan-injected guinea pigs from the effects of the drug, whereas the persistence of insulin deficiency is consistent with an absence of islet B cell regeneration in the streptozotocin-treated animals.
D000496:Alloxan / Q000494:pharmacology*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002452:Cell Count; D005215:Fasting; D006168:Guinea Pigs; D007328:Insulin / Q000097:blood; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects*; D008297:Male; D010179:Pancreas / Q000166:cytology / Q000187:drug effects; D012038:Regeneration / Q000187:drug effects; D013311:Streptozocin / Q000494:pharmacology*; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D013311:Streptozocin; D000496:Alloxan