Abstract
Recent work in our laboratory has shown that a single oral administration of triphenyltin compounds induces insulin-deficient diabetes in rabbits by inhibiting insulin secretion from morphologically intact B cells. The purpose of the present study was to compare the diabetic states induced by triphenyltin hydroxide (TPT) with those induced by alloxan. The results obtained were as follows.
1) Rabbits injected iv with alloxan (150 mg/kg) showed a rapid increase in blood glucose levels at 3 hours with a marked subsequent decrease. This hypoglycemic state was followed by a continued hyperglycemic state. On the other hand, TPT-treated rabbits did not show such a triphasic blood glucose pattern. The blood glucose levels increased steadily after TPT administration, reached a peak level on the 3rd day and then decreased. The different effects of TPT and alloxan on the blood glucose levels appeared to reflect the morphologic changes of islets provoked by these chemicals.
2) In alloxan-treated rabbits, hyperglucagonemia was accompanied with elevation of the fasting blood glucose, free fatty acid (FFA), β-hydroxybutyrate and triglyceride levels, while in TPT-treated rabbits, elevations of these levels were not accompanied by changes in fasting glucagon concentration.
These results suggest that the mobilization of FFA and onset of ketosis in TPT-treated rabbits occur independently of changes in glucagon concentration and that they are primarily induced by insulin deficiency.
