Glucose transport across the blood-retinal barrier (BRB) was investigated in situ by means of a modification of the single-injection technique developed for studying transport across the blood-brain barrier. A retinal uptake index was calculated from the fractional extraction for 14C-glucose divided by the fractional extraction for the 3H2O reference. The use of the Eadie-Hofstee transformation...

Nypa fruticans Wurmb. vinegar, commonly known as nipa palm vinegar (NPV) has been used as a folklore medicine among the Malay community to treat diabetes. Early work has shown that aqueous extract (AE) of NPV exerts a potent antihyperglycemic effect. Thus, this study is conducted to evaluate the effect of AE on postprandial hyperglycemia in an attempt to understand its mechanism of antidiabetic...

Apples are important dietary sources of potentially healthy phenolics. In three successive seasons, the changes in concentrations of flavonoids and chlorogenic acid in the skin of two apple cultivars ‘Jonagold’ and ‘Elstar’ during and after regular (RS) and ultra low oxygen storage (ULO) at 1°C, were quantified by reversed-phase high performance liquid chromatography (RP-HPLC) with UV-VIS detec...

Filtered myo-inositol, an important renal intracellular organic osmolyte, is almost completely reabsorbed. To examine tubule sites and specificity and, thus possible mechanism of this reabsorption, we microinfused myo-[(3)H]inositol or D-[(3)H]glucose into early proximal (EP), late proximal (LP), or early distal tubule sections of superficial nephrons and into long loops of Henle (LLH) of juxta...

Polypeptide constituents of the lens glucose transporter have been identified by photoaffinity labelling with cytochalasin B. The urea-insoluble fraction of monkey lens was irradiated at 280 nm for 30 min in the presence of 5 X 10(-7) M 3H-cytochalasin B. After extensive washing, the membranes were solubilized and their polypeptide composition determined by SDS-PAGE. Radioactivity was extracted...

The effect of in vivo infusion of the peptide hormone glucagon-like peptide 2 (GLP-2) on glucose transport across the rat jejunal brush-border membrane (BBM) was assessed using isolated membrane vesicles. A 2-h infusion of GLP-2 produced a marked acceleration of sodium-dependent glucose uptake into BBM vesicles with a significant overshoot. There was no change in vesicle space or permeability r...

Glucose is an important stimulus for glucagon-like peptide 1 (GLP-1) secretion, but the mechanisms of secretion have not been investigated in integrated physiological models. We studied glucose-stimulated GLP-1 secretion from isolated perfused rat small intestine. Luminal glucose (5% and 20% w/v) stimulated the secretion dose dependently, but vascular glucose was without significant effect at 5...

stimulating insulin release when taken orally (Marks & Samols, 1969), suggesting that its insulin-stimulating effect is mediated through one or more of the intestinal insulin-stimulating hormones. The degree of hyperglycaemia after ingestion of fructose or galactose is similar and small; however, ingestion of galactose elevates circulating concentrations of gastric inhibitory polypeptide, where...

Two distinct transporters for nucleobases have been characterized in LLC-PK1 cells. The first system accumulates hypoxanthine against a concentration gradient in the presence of sodium. The sodium-dependent uptake of hypoxanthine was saturable at 22 degrees C with a Km value of 0.79 +/- 0.43 microM, a Vmax of 15 +/- 4 pmol/mg protein/60 s, and a Na+:hypoxanthine coupling stoichiometry of 1.27 +...

Myoinositol transport by isolated basolateral membrane vesicles was characterized from intestines of the herbivorous tilapia (Oreochromis mossambicus) and the carnivorous eel (Anguilla anguilla). [3H]myoinositol transport occurred by nonelectrogenic, facilitated diffusion independent of cation gradients and was inhibited by phloretin (Ki = 0.6 and 0.9 mM for tilapia and eel, respectively) but n...