Browsing by Author "KAWADA, ME"

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    ADRENAL AND LIVER PARTICIPATION IN RATS POST-STRESS DIABETIC RESPONSE
    (1976) VARGAS, I; KAWADA, ME
    Sixty minutes of restraint stress, preceded by chlorpromazine administration which stimulates somatotropic hormone secretion (STH), produced an acute post-stress diabetic response (PDR) in normal-intact rats and in adrenalectomized rats. This PDR lasted 3-4 h and was evaluated by glucemia and glucosuria determination and by the appearance of an insulin antagonist, .alpha.2-glycoprotein STH-dependent, called .alpha.2-inhibitor, which inhibits glucose uptake by isolated tissues. When tested in the suprahepatic blood of animals after stress it showed increased activity in normal and in adrenalectomized rats. .alpha.2-Inhibitor may be produced in the liver by the action of STH and without primary glucocorticoid participation. The post-stress hyperglucemic response of adrenalectomized rats had a similar tendency to that of the control, although with initial and final values of glucemia significantly below the control. This response supports the idea that postadrenalectomy gluconeogenesis was evoked during and after the systemic stress.
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    CHARACTERIZATION OF HUMAN PEROXISOMAL MEMBRANE-PROTEINS
    (1994) SANTOS, MJ; KAWADA, ME; ESPEEL, M; FIGUEROA, C; ALVAREZ, A; HIDALGO, U; METZ, C
    The peroxisomal membrane appears to play a crucial role in transporting proteins into the organelle. Some human genetic disorders involving peroxisome biogenesis, such as Zellweger syndrome, may be caused by genetic defects of the import machinery located in the peroxisomal membrane. In order to characterize the proteins of the human peroxisomal membrane, we isolated peroxisomes from human liver. We obtained their membranes using various procedures and analyzed their proteins by SDS-polyacrylamide gel electrophoresis and silver staining. We compared the protein composition of peroxisomal membranes with membranes derived from mitochondria and microsomes. The main peroxisomal membrane proteins (PMPs) have apparent molecular masses of 147, 112, 95, 87, 81, 79, 74, 69(70), 53-52 (double band), 47, 45, 43, 37, 31, 28, 22, and 17 kDa. The following PMPs of 147, 112, 79, 69(70), 53-52 (double band), 47, 43, 31, 28, 22, and 17 kDa fit the criteria for integral membrane proteins. We then produced rabbit polyclonal and mouse monoclonal antibodies that recognized some human PMPs. One of these antibodies detected mainly PMP43. We used this antiserum to evaluate the presence and subcellular distribution of the PMP43 in fibroblasts derived from patients affected by Zellweger syndrome. These results represent new information about the protein composition of the human peroxisomal membrane and provide biological tools for further characterization of the human PMPs and their genes in normal and pathological conditions.
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    INDUCTION OF PEROXISOMAL FATTY ACYL-COENZYME A-OXIDASE AND TOTAL CARNITINE ACETYL-COENZYME A-TRANSFERASE IN PRIMARY CULTURES OF RAT HEPATOCYTES BY GARLIC EXTRACTS
    (1992) ORELLANA, A; KAWADA, ME; MORALES, MN; VARGAS, L; BRONFMAN, M
    Garlic has been proposed as a natural hypolipidemic substance. Most hypolipidemic compounds induce peroxisomal proliferation and increase enzyme activities associated with peroxisomal beta-oxidation in rat liver. Here we report that garlic methanol-extracts behave as hypolipidemic drugs, increasing the activity of peroxisomal fatty acyl-coenzyme A oxidase and of total carnitine acetyl-coenzyme A transferase in primary cultures of rat hepatocytes. Both enzymes are considered markers associated with increased peroxisomal beta-oxidation. As in the case of hypolipidemic peroxisome proliferators, garlic extracts partially prevented the decrease in fatty acyl-coenzyme A oxidase as the culture aged. No changes were observed in the activity of microsomal NADPH cytochrome c reductase or of mitochondrial glutamate dehydrogenase.
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    ISOLATION OF PEROXISOMES FROM FROZEN HUMAN LIVER SAMPLES
    (1992) ALVAREZ, A; HIDALGO, U; KAWADA, ME; MUNIZAGA, A; ZUNIGA, A; IBANEZ, L; KOENIG, CS; SANTOS, MJ
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    STRESS HYPERGLYCEMIC RESPONSE AFTER CENTRAL AND PERIPHERAL MONO-AMINERGIC NEURONS DESTRUCTION, OR ADRENAL CATECHOLAMINES DEPRIVATION
    (1982) ROMERO, G; VALDES, EM; YANEZ, MT; KAWADA, ME; VARGAS, L
    Restraint stress of 60 min in unfasted non-diabetic 80%-pancreatectomized rats produced a stress diabetic response with significant glycosuria and hyperglycemia. This model was used to investigate the influence of central noradrenergic, dopaminergic, serotoninergic and peripheral noradrenergic neurons, by means of selective chemical lesion. 6-Hydroxydopamine (6-OH-DA) was used to damage noradrenergic and dopaminergic neurons and 5,6-dihydroxytryptamine for serotoninergic neurons. The sympatho-adrenal system was also studied by adrenal demedullation. Results showed that intracerebro-ventricular administration of 6-OH-DA alone, or followed by 5,6-dihydroxytryptamine, had no influence on the stress hyperglycemic response. Central and peripheral 6-OH-DA administration to intact new born rats did not modify the stress response at the adult age. The hypothalamic monoaminergic and neighboring neurons appear to have no influence in the mechanism of stress hyperglycemia. The pseudo-aggressive behavior which arose after central noradrenergic and dopaminergic lesion, returned to normal after serotoninergic neuron destruction. Bilateral adrenal-medullectomy abolished the stress hyperglycemia. Adrenal catecholamines were necessary for the production of restraint stress hyperglycemia. Among these catecholamines, adrenaline [epinephrine] is proposed as the trigger factor.