Study of the effect of insulinoma on the levels of insulin and glucagon in different rat tissues

The insulinoma tumour was induced by x-irradiation in white male rats. Small fragments of the original tumour were implanted into recepient rats. A group of normal rats were left as control. Plasma glucose levels were determined by glucose oxidase method in both groups tumour bearing rats and control rats. Plasma insulin and the insulin content of the pancreas, tumour, and fraction of gastrointestinal tract extracts were measured by RIA in both groups. Renal, pancreatic and tumour extracts glucagon was measured similarly. Analysis of the weights of the animals and tissues revealed no significant differences between the control and tumour bearing rats. Hyperinsulinemia and hypoglycaemia were observed in the insulinoma bearing rats. Tumour bearing rats showed low concentrations of insulin in the pancreas, and duodenum along with low concentration of glucagon in pancreas. However, control group displayed low concentration of both insulin and glucagon in the colon and ileum respectively. Atrophy of A and B cells of the pancreas of the tumour bearing rats were observed. Measurement of insulin and glucagon in the pancreas revealed significantly lower concentration in the control rats

glucagon et les glucagonomes

Ghucagon is a pancreatic peptide, secreted by the A cells of the pancreatic islets of Langerhans under the influence of a certain number of regulating factors. This 29 amino-acids peptide has essentially a hyperglycemic action because it mobilizes all the organism's energetic reserves, and will therefore oppose insulin hypoglycemias. Its other actions are less known and are only expressed at supraphysiological levels such as its muscle relaxant effect on the digestive smooth muscle fibers, or its cardiac stimulant effect. Some authors have attributed recently to glucagons a role in the regulation of thirst and satiety, and that may lead to some interesting therapeutic actions such as in obesity. Its regulating action on liver cells has not been proven yet at least in severe hepatic lesions. Glucagonomas are rare neuroendocrine tumors, usually malignant, that develop in the endocrine pancreas and have a clinical picture characterized by the presence of the 4 D syndrome [migratory necrolytic dermatitis, diabetes mellitus, deep-vein thrombosis, and depression]. The tumor causing the hyperglucagonemia has a slow growth that explains its often important volume and the existence of metastasis in 60% of the cases at the time of diagnosis. Apart from the metastatic invasion, and as is the case in other neuroendocrine tumors, there are no definite criteria of histological malignancy. The definitive treatment of glucagonoma is surgical removal of the tumor, flanked or not by a treatment with somatostatin analogues that are active because of the existence of somatostatin receptors in neuroendocrine tumors. Radioactive somatostatin is utilized for the detection of metastatic sites but also as a therapeutic tool. Concerning whole-body scanning, the use of radiolabeled somatostatin has proven to be one of the high-performance techniques, but also a very sensitive one. As far as treatment is concerned, somatostatin radioactive analogues are increasingly replacing conventional radiotherapy as well as conventional chemotherapy

Eritema necrolítico migratorio: presentación de un caso y revisión de la literatura / Necrolytic migratory erythema: case and literature review

El eritema necrolítico migratorio es una erupción cutánea característica, con hallazgos histopatológicos específicos que se relacionan frecuentemente con un tumor pancreático, el glucagonoma. Los pacientes con este síndrome son generalmente mal diagnosticados. Se presenta un paciente de 54 años de edad con una erupción cutánea recurrente, pérdida de peso, glositis e hiperglucemia de cuatro meses de duración. Esta importante, pero rara enfermedad, puede ser diagnosticada tempranamente, basándonos en el cuadro cutáneo

Glucose intolerance, insulin resistance and hyperglucagonemia in acute infection

In a trial to find out the effect of infection on glucose homeostasis, fasting and postprandial blood glucose, serum insulin and plasma glucagon were estimated using an anzymatic method and a sensitive RIA respectively in 25 subjects. They were classified into 10 healthy control subjects and 15 non-diabetic patients suffering of acute infection. Patients in acute stage of infection had a statistically significant [P < 0.01] high mean value of postprandial blood glucose, fasting and postprandial serum insulin, plasma glucagon, blood Glucose/Insulin ratio and Insulin/Glucagon ratio compared to controls and patients in recovery stage, whereas a non significant difference was observed between the various studied groups as regards to fasting blood glucose. Patients in recovery stage had a significant [P < 0.01] high mean value of fasting and postprandial serum insulin compared to the controls while fasting and postprandial blood glucose and plasma glucagon showed a non significant difference compared to the controls so, we concluded that acute infections are almost always associated with a decrease in glucose tolerance and insulin resitance together with hyperglucagonemia and this insulin resistance was corrected after a long duration of recovery