Efeitos da tiroidectomia e administração repetida de L-Tiroxina nas desidrogenases da via das fosfopentoses, nos eritrócitos de rato

• Autor(a) principal: Proença, Carlota
• Data de Publicação: 1983
• Outros Autores: Machado, Ana, Martins-Silva, J.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10451/20167

The temporal variations in the activity of erythrocyte glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6-PGD) were studied on thyroidectomized rats (Group I) and upon administration of L-thyroxine to intact rats (Group II). For experiments on Group I, three periods of observation after total thyroidectomy were selected: 1st, 4th and 6th weeks; Group II was subdivided in two subgroups (a and b): (a) the administration of L-thyroxine was made by oral route, ad-libitum (250 ~g/l00 ml water) and the animals were sacrificed from the 4th to the 10th weeks of experiment; (b) The intoxication was produced by repeated intraperitoneal injections in normal rats of 5OjLg/100 g weight, 4 days/week, for a minimum of one week and maximum of four weeks. No significant differences were observed, in each period and experimental conditions, for the G6PD activities; meanwhile, in two intermediate periods of subgroup (a) the 6-PGD activity was increased. The above results have been discussed with reference to some current mechanism, proposed for the action of thyroid hormones on human red cells, suggesting that the direct oxidative pathway of G6P metabolism on rat erythrocytes is less sensitive to the effects of those hormones.