E Oshima — Page 2 | Search PubMed

PubMedDate not supplied

Decreased autophosphorylation and kinase activity of insulin receptors in diabetic Chinese hamsters.

To clarify the role of the insulin receptor in diabetes, the hepatic insulin receptor was investigated in the spontaneously diabetic Chinese hamsters, which are the animal models for insulin-deficient diabetes. Insulin binding in the diabetic animals increased mainly due to an increase in the number of receptors. It was also observed that both the autophosphorylation and kinase activity of the hepatic insulin receptor were decreased in the diabetic animals compared to the control animals. These changes in the hepatic insulin receptor may be caused by the diabetes itself. As the phosphorylated protein of 95 kDa was immunoprecipitated by the anti-insulin receptor antibody (B-10, human) in both diabetics and controls, it was supposed that the 95 kDa protein would be the beta-subunit of insulin receptors, as in other animals. These animals seem to be useful for examining insulin receptors in diabetes.

Animals↗

PubMedDate not supplied

Metabolic and morphological changes of the heart in Chinese hamsters (CHAD strain) with spontaneous long-term diabetes.

We studied the effect of spontaneous long-term (9-10 months) diabetes on the heart of Chinese hamsters (CHAD strain) to elucidate the relationship between diabetes mellitus and cardiomyopathy. The diabetic hamsters, aged approximately 11 months, showed body weight loss, hyperglycemia (mean fasting plasma glucose 402 mg/dl), hypoinsulinemia, hyperlipidemia and ketonemia. The diabetic hamsters showed reduced activities of cytoplasmic glycolytic key enzymes; hexokinase, pyruvate kinase and phosphofructokinase, increases in cardiac glycogen and glucose-6-phosphate contents and a 40% decrease in cardiac ATP content, indicating decreased energy production. An accumulation of myocardial triglyceride and cholesterol was found in the diabetic hamsters. In addition, the cardiac norepinephrine content was increased in the diabetic hamsters, suggesting the presence of autonomic nervous disorder. Increased heart weight and thickening of the septum and both ventricular walls were found in the diabetic hamsters. Light-microscopic analysis revealed that 42.9% of the diabetic hamsters had myocardial degeneration without any vascular lesion of extramural large and intramural small vessels, whereas the non-diabetic controls had no myocardial or vascular lesions. These data suggest that the diabetic Chinese hamsters had cardiomyopathy, which is possibly caused by extravascular factors such as metabolic or autonomic nervous disorder although conclusive evidence is lacking.

Animals↗