RESUMO
Whole-body gamma irradiation of rats induced the formation of lipofuscin-like pigments in erythrocytes. Erythrocytes that were damaged by oxidation were scavenged in the spleen, and lipofuscin-like pigments were transferred from erythrocytes to the spleen during this process. The time course of lipofuscin-like pigments in erythrocytes and spleen indicates that the pigments were not induced by the action of free radicals produced by ionizing radiation but rather were a sequela of postirradiation metabolic changes.
Assuntos
Eritrócitos/efeitos da radiação , Pigmentos Biológicos/biossíntese , Baço/efeitos da radiação , Animais , Biomarcadores , Radioisótopos de Cobalto , Eritrócitos/metabolismo , Raios gama , Lipofuscina , Masculino , Ratos , Ratos Endogâmicos , Baço/metabolismo , Irradiação Corporal TotalRESUMO
The present work was aimed at investigation of lipid peroxidation during fasting and its effects upon metabolism of adipose tissue, especially lipolytic activity. An increase in the lipid peroxidation was demonstrated in an animal model (male rats) through accumulation of lipofuscin-like pigments (LFP), the end product of lipid peroxidation. The increased LFP levels correlated with a decrease in the activity of hormone-sensitive lipase. LFP content increased in the plasma, liver and adipose tissue. The time-course of the changes depended on the initial body mass of the animals. Correlations were found between lipolytic activity and LFP content in adipose tissue and in plasma. In the course of the repeated cycles of fasting--feeding, the changes of LFP and lipolysis were antiparallel to each other. During four cycles, there was a net increase in LFP and a net decrease in lipolysis. The lipolytic activity depended on many factors, among which we identified the initial body mass of animals, their age, and the way of feeding. The results obtained in this animal model enable application of the methods used in the investigation of fasting in obese patients.
Assuntos
Jejum , Peroxidação de Lipídeos , Lipólise , Animais , Masculino , Ratos , Ratos EndogâmicosRESUMO
The content of fluorescing products of lipid peroxidation (LFP) and hormone-stimulated lipolytic activity were determined in rat epididymal adipose tissue during a 29-day interval after whole-body gamma irradiation. An increase in LFP was accompanied by a decrease in lipolytic activity. It is suggested that these effects are interrelated and that the decrease in lipolysis in irradiated, semi fasting rats is an additional deteriorating factor leading to death in some animals.
Assuntos
Peroxidação de Lipídeos/efeitos da radiação , Lipólise/efeitos da radiação , Irradiação Corporal Total , Animais , Radioisótopos de Cobalto , Raios gama , Masculino , Ratos , Ratos Endogâmicos , Fatores de TempoRESUMO
The effect of lipid peroxidation on lipolysis depends on the intactness of the adipocyte plasma membrane. In the intact cells, the norepinephrine-stimulated lipolysis was inhibited, while the basal one was elevated. In the lysed cells, lipid peroxidation had no effect upon hormone-stimulated lipolysis, but the basal one was strongly inhibited. The effects of free radical damage (iron plus ascorbate ions) were compared to those of malondialdehyde, a non-radical product of lipid peroxidation. Although qualitatively similar, deterioration of plasma membrane induced by malondialdehyde was much lower than by free radicals. The changes in lipolytic response to norepinephrine were accompanied by a drastic reduction in the number of beta-adrenergic receptors.
Assuntos
Tecido Adiposo/metabolismo , Peróxidos Lipídicos/metabolismo , Lipólise/efeitos dos fármacos , Malonatos/farmacologia , Malondialdeído/farmacologia , Norepinefrina/farmacologia , Receptores Adrenérgicos beta/metabolismo , Tecido Adiposo/efeitos dos fármacos , Animais , Ácido Ascórbico/farmacologia , Ferro/farmacologia , Masculino , Norepinefrina/antagonistas & inibidores , Ratos , Ratos Endogâmicos , Receptores Adrenérgicos beta/efeitos dos fármacosRESUMO
Pneumococcal teichoic acid inhibits induction of competence in incompetent cells of Pneumococcus. The inhibitory effect is very similar to that observed in the presence of d-glucosamine and d-galactosamine.
