ABSTRACT
The effects of a beta-blocker, propranolol, on the enzyme and isoenzyme activities in the heart muscle in vitro and concomitant histopathology of the component cells of the islets of Langerhans were studied in the Wistar rats after treatment with streptozotocin and isoproterenol. The biochemical data indicated that the isoproterenol induced myocardial infarction (MI) precipitates an acute diabetic response in the rat heart. The superimposition of MI in diabetes mellitus caused significant inhibition of phosphofructokinase and hexokinase in the heart muscle. The lactate dehydrogenase depicted shifting of H-type to M-type in diabetes with or without MI. The drugs, when administered in combination, brought distinctive histopathological changes in beta-cells of the pancreatic islets including degranulation, hyalinosis and a near-total destruction; however A and D cells remained more or less unaffected. The effect of propranolol in diabetes mellitus was uncertain but in MI with or without prior diabetes, the drug inversely altered the activities of all the cardiac enzymes, besides stimulating a mild recuperation of the cells of the endocrine parenchyma.
Subject(s)
Animals , Diabetes Mellitus, Experimental/pathology , Female , Isoenzymes/antagonists & inhibitors , Male , Myocardial Infarction/chemically induced , Oxidoreductases/antagonists & inhibitors , Pancreas/drug effects , Propranolol/pharmacology , Rats , Rats, Inbred StrainsSubject(s)
Animals , Female , Heart/drug effects , Hexokinase/metabolism , Insulin/pharmacology , Islets of Langerhans/drug effects , Isoenzymes , Isoproterenol/toxicity , L-Lactate Dehydrogenase/metabolism , Male , Myocardial Infarction/enzymology , Myocardium/enzymology , Phosphofructokinase-1/metabolism , Propranolol/pharmacology , Rats , Rats, Inbred StrainsABSTRACT
Blood glucose variations and concomitant bioptical cytopathological changes in the pancreatic islets following treatment with certain drugs were studied in the catfish. Glucose loading produced a dose-related hyperglycemia, maximum within 3 hr, while alloxan caused a biphasic rise in glucose level without induction of permanent diabetes. Streptozotocin elicited a monophasic hyperglycemic state at a lower dose and biphasic response at higher doses. Glybenclamide produced hypoglycemia in normal and sham-operated fish; the depancreatized animals were unresponsive to this treatment. In all the cases, normoglycemic values were restituted within 4 days of the treatment. The beta-cells of the islets underwent varying histopathological changes with signs of regenerative activity. A depletion in heavy metal (zinc) in these cells was also evident after treatment with streptozotocin.