Variações das enzimas do ciclo do glioxilato durante a germinação em Glycine Max (L.) Merr

Orientadora: Dra. Déa AmaralDissertaçao (mestrado) -Universidade Federal do Paraná, Setor de Ciências Biológicas, Curso de Pós-Graduação em BioquímicaInclui referências: p. 29-3

Hepatic zonation of carbon and nitrogen fluxes derived from glutamine and ammonia transformations

<p>Abstract</p> <p>Background</p> <p>Glutaminase predominates in periportal hepatocytes and it has been proposed that it determines the glutamine-derived nitrogen flow through the urea cycle. Glutamine-derived urea production should, thus, be considerably faster in periportal hepatocytes. This postulate, based on indirect observations, has not yet been unequivocally demonstrated, making a direct investigation of ureogenesis from glutamine highly desirable.</p> <p>Methods</p> <p>Zonation of glutamine metabolism was investigated in the bivascularly perfused rat liver with [U-¹⁴C]glutamine infusion (0.6 mM) into the portal vein (antegrade perfusion) or into the hepatic vein (retrograde perfusion).</p> <p>Results</p> <p>Ammonia infusion into the hepatic artery in retrograde and antegrade perfusion allowed to promote glutamine metabolism in the periportal region and in the whole liver parenchyma, respectively. The results revealed that the space-normalized glutamine uptake, indicated by ¹⁴CO₂production, gluconeogenesis, lactate production and the associated oxygen uptake, predominates in the periportal region. Periportal predominance was especially pronounced for gluconeogenesis. Ureogenesis, however, tended to be uniformly distributed over the whole liver parenchyma at low ammonia concentrations (up to 1.0 mM); periportal predominance was found only at ammonia concentrations above 1 mM. The proportions between the carbon and nitrogen fluxes in periportal cells are not the same along the liver acinus.</p> <p>Conclusions</p> <p>In conclusion, the results of the present work indicate that the glutaminase activity in periportal hepatocytes is not the rate-controlling step of the glutamine-derived nitrogen flow through the urea cycle. The findings corroborate recent work indicating that ureogenesis is also an important ammonia-detoxifying mechanism in cells situated downstream to the periportal region.</p

Variações das enzimas do ciclo do glioxilato durante a germinação em Glycine Max (L.) Merr

Orientadora: Dra. Déa AmaralDissertaçao (mestrado) -Universidade Federal do Paraná, Setor de Ciências Biológicas, Curso de Pós-Graduação em BioquímicaInclui referências: p. 29-3

Effect of crude extracts of leaves of Smallanthus sonchifolius (yacon) on glycemia in diabetic rats

O presente estudo investigou o efeito do extrato bruto das folhas de yacon, obtido por extração a frio (Y C) ou a quente (Y H), ou por extração hidro-alcoólica (Y E), na glicemia de ratos diabéticos (induzidos por estreptozocina, 50 mg/kg, i.p.) e não diabéticos. Os animais foram tratados por via oral com os extratos (400 mg/kg) ou água por um período de 3, 7, 10 e 14 dias. Após o tratamento, os animais foram anestesiados e amostras de sangue foram coletadas para determinações dos níveis de glicose e creatinina plasmática e da atividade de enzimas (AST, ALT, ALP). Também foi avaliado o consumo de ração, água, volume de urina, peso corporal dos animais e a DL50 do Y E. O tratamento dos animais com Y E, por 14 dias, reduziu a glicemia de ratos diabéticos e não diabéticos. Adicionalmente, o Y E restaurou a atividade das enzimas que estavam alteradas, e melhorou o ganho de peso dos animais diabéticos. Estes resultados demonstraram que a efetividade do extrato de yacon está relacionada ao método de preparação do extrato e ao tempo de tratamento dos animais. O efeito do Y E na glicemia de ratos diabéticos não está relacionado à redução da ingesta ou a interferência do extrato na absorção intestinal de carboidratos.The present study investigated the effect of crude extracts from yacon leaves, obtained by aqueous cold (Y C) or hot (Y H) extraction, or hydro-ethanolic extraction (Y E), on glycemia of the diabetic (induced by streptozotocine, 50 mg/kg, ip) and nondiabetic rats. The animals were treated orally with the extracts (400 mg/kg) or water for 3, 7, 10, and 14 days. After this period, the animals were anesthetized and blood samples were collected for measurement of plasmatic glucose and creatinine and activity of the enzymes (AST, ALT, ALP). Also were evaluated the consumption of food, water, urine volume, body weight of the animals and LD50 of Y E. Treatment with Y E for 14 days reduced glycemia in diabetic and nondiabetic animals. No similar reduction was observed in animals treated with Y C or Y H. Additionally, Y E restored the activity of the plasmatic enzymes that were altered, and improved weight gain in the diabetic animals. These results showed that the effectiveness of the yacon extracts is related to the method of preparation and to the time of treatment. The effect of Y E on glycemia in diabetic rats is not related to reduction of food intake or to interference of the extract with intestinal absorption of carbohydrates

Effect of crude extracts of leaves of Smallanthus sonchifolius (yacon) on glycemia in diabetic rats Efeito do extrato bruto das folhas de Smallanthus sonchifolius (yacon) sobre a glicemia de ratos diabéticos

The present study investigated the effect of crude extracts from yacon leaves, obtained by aqueous cold (Y C) or hot (Y H) extraction, or hydro-ethanolic extraction (Y E), on glycemia of the diabetic (induced by streptozotocine, 50 mg/kg, ip) and nondiabetic rats. The animals were treated orally with the extracts (400 mg/kg) or water for 3, 7, 10, and 14 days. After this period, the animals were anesthetized and blood samples were collected for measurement of plasmatic glucose and creatinine and activity of the enzymes (AST, ALT, ALP). Also were evaluated the consumption of food, water, urine volume, body weight of the animals and LD50 of Y E. Treatment with Y E for 14 days reduced glycemia in diabetic and nondiabetic animals. No similar reduction was observed in animals treated with Y C or Y H. Additionally, Y E restored the activity of the plasmatic enzymes that were altered, and improved weight gain in the diabetic animals. These results showed that the effectiveness of the yacon extracts is related to the method of preparation and to the time of treatment. The effect of Y E on glycemia in diabetic rats is not related to reduction of food intake or to interference of the extract with intestinal absorption of carbohydrates.<br>O presente estudo investigou o efeito do extrato bruto das folhas de yacon, obtido por extração a frio (Y C) ou a quente (Y H), ou por extração hidro-alcoólica (Y E), na glicemia de ratos diabéticos (induzidos por estreptozocina, 50 mg/kg, i.p.) e não diabéticos. Os animais foram tratados por via oral com os extratos (400 mg/kg) ou água por um período de 3, 7, 10 e 14 dias. Após o tratamento, os animais foram anestesiados e amostras de sangue foram coletadas para determinações dos níveis de glicose e creatinina plasmática e da atividade de enzimas (AST, ALT, ALP). Também foi avaliado o consumo de ração, água, volume de urina, peso corporal dos animais e a DL50 do Y E. O tratamento dos animais com Y E, por 14 dias, reduziu a glicemia de ratos diabéticos e não diabéticos. Adicionalmente, o Y E restaurou a atividade das enzimas que estavam alteradas, e melhorou o ganho de peso dos animais diabéticos. Estes resultados demonstraram que a efetividade do extrato de yacon está relacionada ao método de preparação do extrato e ao tempo de tratamento dos animais. O efeito do Y E na glicemia de ratos diabéticos não está relacionado à redução da ingesta ou a interferência do extrato na absorção intestinal de carboidratos