RESUMO
Aqueous extract of Bauhinia megalandra leaves was able to inhibit the intestinal glucose absorption in a concentration-dependent way and additive to phlorizine. Moreover, B. megalandra leaf extract drastically reduced the 14C-glucose uptake by enterocyte brush border membrane vesicles. The B. megalandra leaf extract administrated orally, simultaneously with glucose improved the glucose tolerance with a significant reduction of the 30-min peak. The extract did not have an effect on the glucose tolerance when glucose was administrated subcutaneously.
Assuntos
Bauhinia , Glucose/metabolismo , Hipoglicemiantes/farmacologia , Absorção Intestinal/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/farmacologia , Administração Oral , Animais , Radioisótopos de Carbono/metabolismo , Diabetes Mellitus/prevenção & controle , Glucose/administração & dosagem , Teste de Tolerância a Glucose , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/uso terapêutico , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/metabolismo , Masculino , Microvilosidades/efeitos dos fármacos , Microvilosidades/metabolismo , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Folhas de Planta , Ratos , Ratos Sprague-DawleyRESUMO
1. The hepatic glucose-6-phosphatase (G-6-Pase) kinetic variables from chickens were studied in intact and disrupted microsomes using two substrates: glucose-6-phosphate (G-6-P) and pyrophosphate (PPi). They were studied from embryonic life to 51 d of age. 2. The phosphohydrolase activity studied in the broiler chicken liver microsomes corresponds to a true glucose-6-phosphatase. 3. The enzyme VMAX with both substrates in intact and disrupted microsomes showed 2 maxima: one in 19-d-old embryos and the other in 9-d-old chickens. Pyrophosphatase (PPase) VMAX in intact microsomes was higher than that of the G-6-Pase at all ages studied, except in 12 d embryos and 3-d-old chicks. In disrupted microsomes the VMAX of both enzymatic activities were similar. The G-6-Pase latency was high in the 19-d-old embryos and 51-d-old chickens. 4. The KM for PPi and G-6-Pase decreased when microsomes were disrupted. In intact microsomes the G-6-P KM was low in embryos and 3-d-old chicks and later increased. On the other hand, the PPi KM in intact microsomes showed little change during the animal's life and was lower than that of G-6-P. In disrupted microsomes the KM for both substrates were similar. 5. These results suggest a sequential incorporation of the G-6-Pase system components in the endoplasmic reticulum.
Assuntos
Embrião de Galinha/metabolismo , Galinhas/metabolismo , Difosfatos/farmacocinética , Glucose-6-Fosfatase/farmacocinética , Microssomos Hepáticos/enzimologia , Envelhecimento , Animais , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Consumo de Oxigênio , Monoéster Fosfórico Hidrolases/metabolismoRESUMO
The effect of the administration of seven doses of the hepatocarcinogen thioacetamide on the chemical composition of rat liver nuclear envelope subfractions: associated chromatin, nuclear membranes and pore complex-lamina fraction, is analyzed. No alteration in DNA, RNA or phospholipid content is observed after the hepatocarcinogen treatment. Electrophoretic studies of each subfraction from thioacetamide treated rats show differences in the relative proportions of some polypeptides when compared with the controls. Examination of the wheat germ agglutinin binding polypeptides of each subfraction reveals a decrease in the stain of two pore complex-lamina nucleoporins of 85 and 164 kDa and an increase in one of 93 kDa; this observation can be due to changes in the quantity and/or in the agglutinin binding capacity of the nucleoporin as a result of thioacetamide administration. In view of the participation of nucleoporins in the nucleocytoplasmic transport, the changes observed suggest a relationship between changes of some O-linked N-acetyl glucosamine polypeptides components of the nuclear pore complex and the altered transport of some RNA species observed after thioacetamide administration.