Long-term diabetogenic effect of streptozotocin in rats.
The long-term effects of streptozotocin (30-70 mg/kg) were studied on plasma glucose and insulin levels, islet morphology, and glucose-stimulated insulin secretion in rats. In addition, the protective effect of short-term (7 days) insulin treatment on streptozotocin-induced diabetes was examined. Streptozotocin administration at dose levels exceeding 40 mg/kg resulted in a long-term, stable hyperglycemia with no insulin response to glucose at 3 months and with a marked derangement of islet morphology (few insulin cells, accumulation of glucagon cells). In contrast, at 30 and 40 mg/kg, streptozotocin induced a transient diabetes. Thus, the blood glucose levels, being elevated at days 1-7, returned to normal levels within 10 days after streptozotocin administration and the glucose-induced insulin secretion, being absent at day 1, was normal at 3 months. Furthermore, the islet morphology was also normal in these groups at 3 months. Short-term (7 days) insulin treatment normalized the long-term diabetes in rats given 50 mg/kg streptozotocin, but not in rats given 60 or 70 mg/kg streptozotocin. Thus, after insulin treatment, all rats receiving 50 mg/kg streptozotocin returned to normoglycemia within the following 2 weeks, and the glucose-induced insulin secretion was normal after 3 months, as was islet morphology.(ABSTRACT TRUNCATED AT 250 WORDS)
Ar'Rajab
A
A
Department of Surgery, Lund University, Sweden.
Ahrén
B
B
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D005934:Glucagon / Q000378:metabolism; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin / Q000008:administration & dosage / Q000633:toxicity*; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D013311:Streptozocin; D005934:Glucagon