Phosphorylase activation hypersensitivity in hearts of diabetic rats
| Autor: | T. B. Miller |
|---|---|
| Rok vydání: | 1984 |
| Předmět: |
Male
medicine.medical_specialty Epinephrine Phosphorylases Phosphorylase Kinase Physiology Endocrinology Diabetes and Metabolism chemistry.chemical_element Calcium Glucagon Calcium in biology Diabetes Mellitus Experimental Glycogen phosphorylase Physiology (medical) Internal medicine Cyclic AMP medicine Animals Phosphorylase Phosphatase Phosphorylase kinase Protein kinase A Calcium metabolism Chemistry Myocardium Heart Rats Inbred Strains Rats Enzyme Activation Perfusion Endocrinology Protein Kinases medicine.drug |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 246:E134-E140 |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.1984.246.2.e134 |
| Popis: | A hypersensitivity of glycogen phosphorylase activation by epinephrine and glucagon has been demonstrated in isolated perfused working and non-working hearts from diabetic rats. Accumulation of tissue cAMP and activation of cAMP-dependent protein kinase in response to epinephrine and glucagon were no greater and usually less in hearts of diabetic than of normal rats. Insulin deficiency was not associated with greater changes in epinephrine-induced activation of glycogen phosphorylase kinase than that observed in normal hearts. Perfusion of hearts with subphysiological concentrations of calcium (0.83 mM) partially reversed the diabetes-related hypersensitivity of phosphorylase activation by epinephrine. The phosphorylase activation hypersensitivity to epinephrine was completely reversed by adrenalectomizing diabetic rats 5 days before heart perfusion, an effect potentially caused by steroid-induced changes in cardiac calcium metabolism. These data are consistent with the hypothesis that phosphorylase activation by phosphorylase kinase is allosterically increased in the diabetic due to a diabetes-related increase in free intracellular calcium concentrations. |
| Databáze: | OpenAIRE |
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