Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros










Filtros aplicados
Base de dados
Intervalo de ano de publicação
1.
Exp Pathol Jena ; 18(4): 245-53, 1980.
Artigo em Inglês | MedCarib | ID: med-3186

RESUMO

In magnesium deficient rats with a clinical picture of protein malnutrition, pancreatic changes typical of protein malnutrition were expected. However, in rats fed for four weeks on a low magnesium diet (protein content 25 percent), light and electron microscopic studies revealed that the ascinar cells of the pancreas were packed with zymogen granules, suggesting a disturbance in the discharge (rather than in the production) of the pancreatic enzymes. The mitochondria and the lumina of the RER were swollen. The nuclei had an irregular outline, the chromatin was aggregated into irregular granules and the nucleolemma of the nucleolus was fibrillar. It was suggested that the disturbance in the release of pancreatic enzymes might cause a maldigestion of the dietary protein, which eventually would lead to the condition of protein malnutrition in the magnesium deficient rats. The disturbance of exocytosis in the pancreas of magnesium deficient rats might be due to the preferential use of all the available magnesium for protein (enzymes) synthesis so that there were no magnesium ions left for the energy dependent discharge of the zymogen granules (AU).


Assuntos
21003 , Masculino , Ratos , Deficiência de Magnésio/patologia , Pâncreas/ultraestrutura , Núcleo Celular/ultraestrutura , Grânulos Citoplasmáticos/ultraestrutura , Mitocôndrias/ultraestrutura , Retículo Endoplasmático/ultraestrutura , Complexo de Golgi/ultraestrutura , Junções Intercelulares/ultraestrutura , Microscopia Eletrônica , Ribossomos/ultraestrutura
3.
Diabetes ; 21(Suppl 2): 447-52, 1972.
Artigo em Inglês | MedCarib | ID: med-14536

RESUMO

The mechanism by which insulin controls protein metabolism is not fully understood. Insulin stimulates protein synthesis; it also enhances transport of some amino acids, but the latter action does not appear to be sufficient explanation of the increase in synthesis. The various actions seem to be independent of the effects of glucose metabolism. In diabetic muscle there are a fewer than normal polysomes, and insulin rapidly enhances attachment of monomers to messenger-RNA. Insulin also increases the effectiveness of cell sap in catalyzing protein synthesis by ribosomal systems. The way in which the hormone may affect either initiation or peptide synthesis is not known. Experiments are reported bearing on whether availability of amino acids could be a mechanism by which effects of insulin are mediated. Activity of liver and muscle soluble fractions declines on fasting and, for the latter tissue, possibly also on a low protein diet. Sap from fasting animals allows a much smaller response of isolated ribosomes to added amino acids. Availability of glutamate in amino acid mixtures may be of special importance. However, insulin can influence the activity of the sap fraction of diaphram muscle during incubation without the presence of amino acids in the medium. Understanding of what mechanisms are involved will depend on resolution of the critical sap factors (Summary)


Assuntos
Humanos , Insulina/metabolismo , Proteínas/biossíntese , Ribossomos/fisiologia , Aminoácidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...