Intestinal uptake of fatty acids and cholesterol in four animals species and man: role of unstirred water layer and bile salt micelle

The uptake (Jd) of fatty acids (FA), fatty alcohols (Alc) and cholesterol (C) into the jejunum of rats (R, Rattus norvegicus), rabbits (RAB, Oryctolagus cuniculus), guinea pigs (GB, Cavia porcellus), and hamsters (H, Mesocricetus auratus) was assessed in vitro. Using jejunal discs the Jd of Alc was H greater than R = GP greater than RAB, the Jd of FA was H-RAB greater than R greater than GP, but the Jd of C was R greater than H greater than RAB greater than GP. The Jd of FA was quantitatively and qualitatively different when using jejunal biopsies; in man the Jd of FA into biopsies was greater than in the other animal species, but there was no difference in Jd of FA into normal human jejunal biopsies and those showing severe abnormalities in villus architecture. There are marked species differences in the passive permeability properties of the jejunum and in the effective resistance of the overlying unstirred water layer, but these differences do not explain the species variations in the uptake of cholesterol.     

Solute transport into healthy and powdery mildew-infected leaves of pea and uptake by powdery mildew mycelium

The transport of sugars and amino acids into the mycelium of Erysiphe pisi DC. was investigated using two different systems, intact leaf discs and mycelial suspensions. Of the sugars tested, glucose was preferentially taken up by both uninfected and mildew-infected leaf discs, whereas glutamine was taken up by both tissues at a higher rate than lysine or aspartic acid. Leaf discs from infected tissue had a greater uptake capacity than those from healthy tissue for both sugars and amino acids. The uptake of glucose was inhibited more markedly than that of sucrose and fructose by 10 μ m carbonyl cyanide m -chlorophenylhydrazone (CCCP), 1 m m N -ethylmaleimide (NEM), 1 m m diethyl pyrocarbonate (DEPC) and 1 m m phenylglyoxal, whereas 1 m m PCMBS ( p -chloro-mercuribenzenesulphonic acid) inhibited sucrose uptake to the greatest extent. Uptake of glutamine, lysine and aspartic acid was inhibited similarly by CCCP (80%), NEM (20%), DEPC (70%) and PCMBS (60%). Additionally, leaf discs were used to determine which solutes could be taken up from leaf tissue by the fungus. The uptake of sugars into the mycelium was greater than that of amino acids.
Suspensions of powdery mildew mycelium accumulated glucose at about three times the rate of sucrose or fructose, and the amino acid glutamine was taken up at three times the rate of lysine or aspartic acid. Spores separated from the suspension had a low uptake capacity.
When the reducing sugar concentration of leaf apoplastic fluid was estimated, leaves infected by powdery mildew had much higher amounts in the apoplast, whereas the activity of acid invertase also appeared to be higher in apoplastic fluids from infected leaves. When apoplastic fluid samples were run on SDS gels, an invertase antibody detected two bands in samples from infected tissues that were not found in the uninfected samples.     

Effects of insulin infusion on glucose kinetics in normal and burned guinea pigs

The effects of a constant infusion of insulin (12 mu/kg·min for 90 min) on glucose turnover (determined by means of the primed-constant infusion of 6-³H-glucose) was evaluated in normal and burned (50% BSA) guinea pigs (gp). In burned, untreated gp, the mean plasma glucose level (gl) was increased from 129±8.2 to 205±13.7 mg/dl 90 min after burning, whereas gl was 140±14.5 mg/dl in the burned + insulin-infused animals at 90 min. The insulin infusion reduced gl from 120±5.6 to 69±5.8 mg/dl in unburned gp; the rate of glucose appearance (R_a) was reduced and the metabolic clearance rate (MCR) was increased. In the B+I gp, the insulin effectively minimized the increase in R_a which followed burning in the burned, untreated gp. However, insulin did not increase the MCR of the burned + insulin-infused group above that of the burned, untreated group. On the day following the burn, the insulin infusion decreased gl in the burned gp to the same extent as in the unburned animals and also increased MCR. We concluded that whereas there was a lack of peripheral responsiveness to the insulin infusion in the first 90 min after burning (during the shock phase), no such lack of responsiveness was evident on the second day.     

Novel, chimpanzee serotype 68-based adenoviral vaccine carrier for induction of antibodies to a transgene product

An E1-deletion-containing adenoviral recombinant based on the chimpanzee serotype 68 (AdC68) was developed to express the rabies virus glycoprotein. Mice immunized with this construct (AdC68rab.gp) developed antibodies to rabies virus and remained resistant to challenge with an otherwise lethal dose of rabies virus. In na?ve mice immunized intranasally, the rabies virus-specific antibody responses elicited by AdC68rab.gp were comparable with regard to both titers and isotype profiles to those induced by an adenoviral recombinant based on human serotype 5 (Adhu5) expressing the same transgene product. In contrast, subcutaneous immunization with the AdC68rab.gp vaccine resulted in markedly lower antibody responses to the rabies virus glycoprotein than the corresponding Adhu5 vaccine. Antibodies from AdC68rab.gp-immunized mice were strongly biased towards the immunoglobulin G2a isotype. The antibody response to the rabies virus glycoprotein presented by Adhu5rab.gp was severely compromised in animals preexposed to the homologous adenovirus. In contrast, the rabies virus-specific antibody response to the AdC68rab.gp vaccine was at most marginally affected by preexisting immunity to common human adenovirus serotypes, such as 2, 4, 5, 7, and 12. This novel vaccine carrier thus offers a distinct advantage over adenoviral vaccines based on common human serotypes.     

Effect of prior exercise on glucose metabolism in trained men

Several studies have demonstrated that oral glucose tolerance is impaired in the immediate postexercise period. A double-tracer technique was used to examine glucose kinetics during a 2-h oral glucose (75 g) tolerance test (OGTT) 30 min after exercise (Ex, 55 min at 71 +/- 2% of peak O(2) uptake) and 24 h after exercise (Rest) in endurance-trained men. The area under the plasma glucose curve was 71% greater in Ex than in Rest (P = 0.01). The higher glucose response occurred even though whole body rate of glucose disappearance was 24% higher after exercise (P = 0.04, main effect). Whole body rate of glucose appearance was 25% higher after exercise (P = 0.03, main effect). There were no differences in total (2 h) endogenous glucose appearance (R(a)E) or the magnitude of suppression of R(a)E, although R(a)E was higher from 15 to 30 min during the OGTT in Ex. However, the cumulative appearance of oral glucose was 30% higher in Ex (P = 0.03, main effect). There were no differences in glucose clearance rate or plasma insulin responses between the two conditions. These results suggest that adaptations in splanchnic tissues by prior exercise facilitate greater glucose output from the splanchnic region after glucose ingestion, resulting in a greater glycemic response and, consequently, a greater rate of whole body glucose uptake.     

Stimulation of glucose uptake in skeletal muscle using bolus or continuous insulin delivery

We investigated glucose uptake in the non-cyclically perfused rat hindlimb in response to continuous infusion (CI) or bolus injection (BI) of insulin. Ten mM glucose was infused at 3 ml/min, venous glucose was monitored at two minute intervals, and glucose uptake was calculated on the basis of arteriovenous-difference and expressed as micron/min/100 g body wt. Insulin BI given every ten minutes equaled the amount of insulin given by CI for ten minutes. Insulin doses of 1500, 3000, 6000, and 45,000 microU/30 min showed no significant difference between the two modes of delivery in either onset of stimulation or maximal stimulation of glucose uptake. At the lowest insulin dose tested (1500 microU/30 min) neither BI nor CI stimulated glucose uptake above the control of 1.849 micron/min/100 g. A dose response curve for glucose uptake was obtained using insulin boluses ranging from 2000 to 20,000 microU. Insulin uptake by the muscle was always greater when insulin was administered CI. Net disappearance of immunoreactive insulin over the entire 30 minutes of perfusion was 29.4 +/- 2.6% for CI but only 7.1 +/- 1.6% for BI. Thus in the perfused rat hindlimb, stimulation of glucose uptake in skeletal muscle is comparable with BI and CI delivery of insulin but insulin uptake by the muscle is several-fold greater with CI delivery.     

Evaluation of Glucose Absorption Level in the Small Intestine of Different Rat Strains under Natural Conditions

The peculiarities of carbohydrate metabolism were studied in seven rat strains under conditions maximally approximating natural ones. The glucose absorption level in the small intestine was evaluated using a method based on ad libitum drinking of concentrated glucose solutions by prefasted (18–20 h) rats. It was shown that in the steady-state regime the volume-normalized uptake rate of glucose solution (mL/min) was constant and inversely proportional to the glucose concentration in the solution, while the uptake rate of glucose itself (μmol/min) was independent of the substrate concentration in quite a wide range, being mainly determined by the absorptive capacity of the small intestine. A significant difference was revealed between the tested rat strains in terms of the rate of glucose absorption from its solution (200 g/L). In the daytime (10 AM–4 PM), the highest rates were observed in Sprague Dawley rats (116.7 ± 3.1 μmol/min) while the lowest—in Wistar Kyoto rats (35.6 ± 1.1 μmol/min). In the evening (4–10 PM), rates of glucose absorption in different rat strains were 1.3–2.2 times higher than in the daytime. Apparently, the increased absorptive capacity of the small intestine in the evening is due to enhanced SGLT1-mediated active glucose transport and reflects the peculiarities of carbohydrate metabolism regulation in different rat strains.     

Sugar transport in rat liver lysosomes. Direct demonstration by using labelled sugars.

Purified rat liver lysosomes ('tritosomes') were prepared from rats injected with Triton WR-1339. 2. The water space of tritosomes, measured by using [3H]water and [14C]sucrose, was 2.15 +/- 0.72 microliter/mg of protein (mean +/- S.E.M., n = 12). 3. Tritosomes, when compared with a crude preparation of normal lysosomes by an indirect method of study, showed sugar specificity but decreased stereospecificity of sugar uptake. 4. At 125 mM the relative rates of net uptake of D-[14C]ribose, D-[14C]- or D-[3H]glucose and 2-deoxy-D-[3H]glucose were the same as that inferred from the indirect study. 5. The entry of D-[3H]glucose into tritosomes showed concentration-dependence suggestive of saturation, with a Km of 48 +/- 18 mM (4). 6. D- and L-glucose, D-ribose, 2-deoxy-D-glucose and D-mannose competed with D-[14C]glucose or D-[14C]ribose for uptake. 7. Cytochalasin B inhibited D-[3H]glucose uptake. 8. Uptake of 1 mM-L-[14C]glucose was slower than for 1 mM-D-[14C]glucose. 9. It is concluded that a facilitated-diffusion transport system is present in purified rat liver lysosomes.     

A phosphorylated phloretin derivative. Synthesis and effect on intestinal Na(+)-dependent phosphate absorption

2'-Phosphophloretin (2'-PP), a phosphorylated derivative of the plant chalcone, was synthesized. The effect of 2'-PP, on Na(+)-dependent phosphate uptake into intestinal brush-border membrane vesicles (BBMV) isolated from rabbit and rat duodenum and jejunum was examined. 2'-PP decreased Na(+)-dependent phosphate uptake into rabbit BBMV with an IC(50) of 55 nM and into rat BBMV with an IC(50) of 58 nM. 2'-PP did not affect Na(+)-dependent glucose, Na(+)-dependent sulfate, or Na(+)-dependent alanine uptake by rabbit intestinal BBMVs. 2'-PP inhibition of rabbit intestinal BBMV Na(+)-dependent phosphate uptake was sensitive to external phosphate concentration, suggesting that 2'-PP inhibition of Na(+)-dependent phosphate uptake was competitive with respect to phosphate. Binding of [(3)H]2'-PP to rabbit intestinal BBMV was examined. Binding of [(3)H]2'-PP was Na(+)-dependent with a K(0.5) for Na(+)(Na(+) concentration for 50% 2'-PP binding) of 30 mM. The apparent K(s) for Na(+)-dependent [(3)H]2'-PP binding to rabbit BBMVs was 58 nM in agreement with the IC(50) for 2'-PP inhibition of Na(+)-dependent phosphate uptake. These results indicate that 2'-PP bound to rabbit or rat intestinal BBMV Na(+)-phosphate cotransporter and inhibited Na(+)-dependent phosphate uptake. In rats treated with 2'-PP by daily gavage, the effect of 2'-PP on serum phosphate, serum glucose, and serum calcium was examined. In a concentration-dependent manner, 2'-PP reduced serum phosphate by 45% 1 wk after starting treatment. 2'-PP did not alter serum calcium or serum glucose. The apparent IC(50) for 2'-PP in vivo was 3 microM.     

Seasonal glucose uptake in marmots (Marmota flaviventris): the role of pancreatic hormones.

1. Glucose uptake was measured throughout the year in marmots (Marmota flaviventris) by the hyperglycemic clamp technique. During each 2 hr experiment, the plasma glucose level was maintained at 215 mg/dl while blood samples were collected and analysed for glucose, insulin, glucagon, cortisol and catecholamines. 2. Glucose uptake was calculated from the glucose infusion rate, changes in the glucose pool (using a correction factor), and urinary glucose excretion. 3. In autumn, animals peaked in body weight (greater than 4.0 kg) and ceased to feed. Basal plasma insulin levels in autumn were significantly elevated over all other seasons (P less than 0.01) and glucose uptake in autumn was 9.7 +/- 2.4 mg/min which was significantly lower (P less than 0.05) than summer (21.7 +/- 2.4 mg/min) during the steady state phase of the glucose clamp (90-120 min). 4. Plasma glucagon levels declined during the clamp in all seasons but there was no significant difference between seasons. Plasma cortisol and catecholamine (norepinephrine and epinephrine) levels remained unchanged under basal and experimental conditions throughout the seasons. 5. During glucose infusion, beta-hydroxybutyrate levels were suppressed suggesting that lipolysis was reduced during the experiment. 6. These results suggest that the marmot exhibits seasonal changes in glucose uptake; the lowest rate of glucose uptake occurring in the autumn after the animals peak in body weight and cease to feed.     

Non-uniformities in the metabolism of excised leaves and leaf discs

Summary In intact tobacco and Chinese-cabbage (Brassica pekinensis) leaves an ageing process begins as soon as the leaves are excised. The terminal few millimetres of the petiole increasingly preempt materials such as phosphate and uracil taken up by the leaf. Actinomycin D treatment blocks this process and leads to increased uptake of such materials into the lamina.Immediately after excision there is a radial geographical gradient, in the ability of excised leaf discs to accumulate phosphate and uracil from solution. Tissue near the cut edge accumulates much more of these materials than that near the centre, and total nucleic acids isolated from the outer zone have a higher specific activity.Over the first day after excision there is a marked increase in this ability of the outer tissue of discs to accumulate labelled precursors but the changes taking place with time are complex and variable. Specific activity of total nucleic acids increases somewhat less than the increased uptake of labelled precursor. Actinomycin D becomes very unevenly distributed in leaf discs floated on solutions of the drug. These various effects are of sufficient magnitude to affect the interpretation of studies using excised leaf tissues.     

Coordinate regulation of catecholamine uptake by rab3 and phosphoinositide 3-kinase.

Previously we observed that rab3 GTPases modulate both the secretion of catecholamines from PC12 neuroendocrine cells and the steady-state accumulation of exogenous norepinephrine (NE) into these cells (Weber, E., Jilling, T., and Kirk, K. L. (1996) J. Biol. Chem. 271, 6963-6971). Here we addressed the mechanisms by which these monomeric GTPases stimulate NE uptake by PC12 cells including their effects on uptake kinetics, their sites of action (secretory granule membrane versus plasma membrane), and the involvement of rab3-interacting proteins in this process. We observed that rab3B stimulated the rate and maximal accumulation of radiolabeled NE into large dense core vesicles within intact PC12 cells. rab3A and rab3B also increased NE uptake into large dense core vesicles in digitonin-permeabilized PC12 cells, which indicates that these GTPases stimulate catecholamine uptake at the level of the secretory granule membrane. In an attempt to identify rab3B targets that may mediate this effect on NE uptake, we found that rab3B interacts directly with phosphoinositide 3-kinase (PI3K) in a GTP-dependent fashion and that PI3K activity was elevated in PC12 cells overexpressing rab3B. Furthermore, two structurally distinct inhibitors of PI3K (wortmannin and LY294002) inhibited NE uptake in intact as well as digitonin-permeabilized PC12 cells, but had no effect on calcium-evoked NE secretion. Our results indicate that rab3 and PI3K positively and coordinately regulate NE uptake in PC12 neuroendocrine cells at least in part by stimulating the secretory vesicle uptake step.     

Glucose Metabolism in Sediments of a Eutrophic Lake: Tracer Analysis of Uptake and Product Formation

The uptake of glucose and the formation of end products from glucose catabolism have been measured for sediments of eutrophic Wintergreen Lake with a combination of tritiated and ¹⁴C-labeled tracers. Time course analyses of the loss of [³H]glucose from sediments were used to establish rate constants for glucose uptake at natural substrate concentrations. Turnover times from these analyses were about 1 min for littoral and profundal sediments. No seasonal or site differences were noted in turnover times. Time course analyses of [U-¹⁴C]glucose uptake and ¹⁴C-labeled end product formation indicated that glucose mass flow could not be calculated from end product formation since the specific activity of added [¹⁴C]glucose was significantly diluted by pools of intracellular glucose and glucose metabolites. Mass flow could only be accurately estimated by use of rates of uptake from tracer studies. Intermediate fermentation end products included acetate (71%), propionate (15%), lactate (9%), and only minor amounts of butyrates or valerates. Addition of H₂ to sediments resulted in greater production of lactate (28%) and decreased formation of acetate (50%), but did not affect glucose turnover. Depth profiles of glucose uptake indicated that rates of uptake decreased with depth over the 0- to 18-cm interval and that glucose uptake accounted for 30 to 40% of methanogenesis in profundal sediments.     

Development Capacities of Mixed Normal and Neoplastic 1(3)gl Imaginal Discs and Neuroblast Tissue in Drosophila hydei

The pleiotropic mutant lethal(3)giant larvae [l(3)gl] of Drosophila hydei exhibits among other anatomical defects, hypertrophy of the larval brain and imaginal discs. Both hypertrophic tissues when transplanted into wild-type female flies behave as fast growing and lethal neoplasms. Implanted into mature wild-type larvae they fail to metamorphose. When l(3)gl neoplastic brain tissue or imaginal discs were mixed with normal imaginal discs, cultured in vivo in the abdomen of adult females and transplanted into mature wild-type larvae, the following results were obtained. The invasive l(3)gl brain neoplasm, while fatal for adult hosts, had no effect on the metamorphosis of normal imaginal disc tissue. On the other hand, the noninvasive l(3)gl imaginal disc neoplasms when mixed with normal imaginal disc tissue inhibited its development and metamorphosis in the wild-type host. This inhibitory effect was not observed when the tissues were injected as separate implants into the same host.     

Production of 2,3‐butanediol by Klebsiella oxytoca from various sugars in microalgal hydrolysate

A new fermentation process using a mixed sugar medium is proposed in this study for 2,3‐butanediol (2,3‐BDO) production. The medium contained seven different monosugars known to be present in Nannochloropsis oceanica hydrolysate. The performance of each sugar when existing alone or together with glucose was evaluated. All the sugars except fucose were successfully metabolized for 2,3‐BDO production. A 2,3‐BDO yield of 0.31g/g was achieved with the mixed sugar medium, which was very close to that with the glucose‐only medium. However, the 2,3‐BDO productivity (0.28 g L^?1 h^?1) was found to be about 30% lower than that with glucose, implying, as expected, the existence of glucose repression on the uptake of other sugars. Strain development is in need to remove such negative effect of glucose for improved process efficiency. Fucose with the lowest uptake rate and no contribution to 2,3‐BDO production can be a high value‐added byproduct, once recovered and purified. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1669–1675, 2015     

Fluid phase endocytosis of [125I]iodixanol in rat liver parenchymal, endothelial and Kupffer cells

Endocytosis of [125I]iodixanol was studied in vivo and in vitro in rat liver cells to determine fluid phase endocytic activity in different liver cells (hepatocytes, Kupffer cells and endothelial cells). The Kupffer cells were more active in the uptake of [l25I]iodixanol than parenchymal cells or endothelial cells. Inhibition of endocytic uptake via clathrin-coated pits (by potassium depletion and hypertonic medium) reduced uptake of [125I]iodixanol much more in Kupffer cells and endothelial cells than in hepatocytes. To gain further information about the importance of clathrin-mediated fluid phase endocytosis, the expression of proteins known to be components of the endocytic machinery was investigated. Using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting, endothelial cells and Kupffer cells were found to express approximately fourfold more rab4, rab5 and rab7 than parenchymal cells, while clathrin was expressed at a higher level in endothelial cells than in Kupffer cells and hepatocytes. Using electron microscopy it was shown that liver endothelial cells contained approximately twice as many coated pits per membrane unit than the parenchymal and Kupffer cells, thus confirming the immunoblotting results concerning clathrin expression. Electron microscopy on isolated liver cells following fluid phase uptake of horseradish peroxidase (HRP) showed that HRP-containing organelles had a different morphology in the different cell types: In the liver endothelial cells HRP was in small, tubular endosomes, while in Kupffer cells HRP was mainly found in larger structures, reminiscent of macropinosomes. Parenchymal cells contained HRP in small vacuolar endosomes with a punctuated distribution. In conclusion, we find that the Kupffer cells and the endothelial cells have a higher pinocytic activity than the hepatocytes. The hepatocytes do, however, account for most of the total hepatic uptake. The fluid phase endocytosis in liver endothelial cells depends mainly on clathrin-mediated endocytosis, while the parenchymal cells have additional clathrin-independent mechanisms that may play an important role in the uptake of plasma membrane components. In the Kupffer cells the major uptake of fluid phase markers seems to take place via a macropinocytic mechanism.     

Role of facilitative glucose transporters in diffusional water permeability through J774 cells

We have reported previously that in the presence of an osmotic gradient, facilitative glucose transporters (GLUTs) act as a transmembrane pathway for water flow. Here, we find evidence that they also allow water passage in the absence of an osmotic gradient. We applied the linear diffusion technique to measure the diffusional permeability (Pd) of tritiated water (3H-H2O) through plasma membranes of J774 murine macrophage-like cells. Untreated cells had a Pd of 30.9 +/- 1.8 microns/s; the inhibitors of facilitative glucose transport cytochalasin B (10 microM) and phloretin (20 microM) reduced that value to 15.3 +/- 1.8 (50%) and 11.0 +/- 0.7 (62%) microns/s, respectively. In contrast, no significant effect on Pd was observed in cells treated with dihydrocytochalasin B (Pd = 28.4 +/- 1.5 microns/s). PCMBS (3 mM) inhibited glucose uptake by greater than 95%, and 3H-H2O diffusion by approximately 30% (Pd = 22.9 +/- 1.5 microns/s). The combination of cytochalasin B plus pCMBS reduced Pd by about 87% (Pd = 3.9 +/- 0.3 microns/s). Moreover, 1 mM pCMBS did not affect the osmotic water permeability in Xenopus laevis oocytes expressing the brain/erythroid form of facilitative glucose transporters (GLUT1). These results indicate for the first time that about half of the total Pd of J774 cells may be accounted for by water passage across GLUTs. Hence, they highlight the multifunctional properties of these transporters serving as conduits for both water and glucose. Our results also suggest for the first time that pCMBS blocks glucose transport without affecting water permeation through GLUTs. Lastly, because pCMBS decreases the Pd of J774 cells, this suggests the presence in their plasma membranes of another protein(s) exhibiting water channel properties.     

Effect of insulin on the glucose utilization in isolated cardiac myocytes from adult rat

The acute effects of insulin on glucose utilization in isolated rat quiescent cardiac myocytes were studied. Insulin (80 nM) increased the rate of glucose clearance by 2-3 times in the presence of glucose ranging from 0.3 microM to 5.5 mM. Glucose transport, which was measured in terms of both D-glucose uptake in the presence of 0.3 microM D-glucose and initial rate of uptake of 3-O-methylglucose, was stimulated 3-fold in the presence of insulin. At higher glucose concentrations (greater than 100 microM), a decrease in glucose clearance rate due to a shift of the rate-limiting step from glucose transport to a post-transport step in the pathway of glucose metabolism was observed. At the physiological concentration of glucose (5.5 mM), about 73% of glucose was metabolized into lactate, about 10% was oxidized into CO2 and the rest (17%) remained inside the cells. The pentose phosphate pathway did not contribute to the glucose metabolism in these cells. Insulin (80 nM) significantly increased the uptake of glucose (112%), and the conversions of glucose into lactate (16%), glycogen (64%), and triglyceride (18%), but not into CO2 (3%). Insulin transiently increased the percentage of I-form of glycogen synthase by 16% above basal, but did not affect the percentage of a-form of glycogen phosphorylase. The content of glucose 6-phosphate in the cells was increased by 46% above the basal value in the presence of insulin. These results indicate that insulin has different acute stimulatory effects on various steps in the metabolic pathway of glucose in isolated quiescent cardiac myocytes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Depot-specific effects of the PPAR�� agonist rosiglitazone on adipose tissue glucose uptake and metabolism

We investigated mechanisms whereby peroxisome proliferator-activated receptor γ (PPARγ) agonism redistributes lipid from visceral (VF) toward subcutaneous fat (SF) by studying the impact of PPARγ activation on VF and SF glucose uptake and metabolism, lipogenesis, and enzymes involved in triacylglycerol (TAG) synthesis. VF (retroperitoneal) and SF (inguinal) of rats treated or not for 7 days with rosiglitazone (15 mg/kg/day) were evaluated in vivo for glucose uptake and lipogenesis and in vitro for glucose metabolism, gene expression, and activities of glycerolphosphate acyltransferase (GPAT), phosphatidate phosphatase-1 (or lipin-1), and diacylglycerol acyltransferase. Rosiglitazone increased SF glucose uptake, GLUT4 mRNA, and insulin-stimulated glucose oxidation, conversion to lactate, glycogen, and the glycerol and fatty acid components of TAG. In VF, only glucose incorporation into TAG-glycerol was stimulated by rosiglitazone and less so than in SF (1.5- vs. 3-fold). mRNA levels of proteins involved in glycolysis, Krebs cycle, glycogen synthesis, and lipogenesis were markedly upregulated by rosiglitazone in SF and again less so in VF. Rosiglitazone activated TAG-glycerol synthesis in vivo (2.8- vs. 1.9-fold) and lipin activity (4.6- vs. 1.5-fold) more strongly in SF than VF, whereas GPAT activity was increased similarly in both depots. The preferential increase in glucose uptake and intracellular metabolism in SF contributes to the PPARγ-mediated redistribution of TAG from VF to SF, which in turn favors global insulin sensitization.     

Mucosally delivered E1-deleted adenoviral vaccine carriers induce transgene product-specific antibody responses in neonatal mice

E1-deleted adenoviral vectors of the human serotype 5 (AdHu5) and the chimpanzee serotype 68 (AdC68) expressing the rabies virus glycoprotein (rab.gp) were tested for induction of transgene product-specific Abs upon intranasal or oral immunization of newborn mice. Both vectors induced Abs to rabies virus that could be detected in serum and from mucosal secretions. Serum rabies virus neutralizing Ab titers sufficed to protect neonatally vaccinated mice against a subsequent challenge with rabies virus. The efficacy of the AdHu5rab.gp vector given orally to newborn mice born to AdHu5 virus-immune dams was not impaired by maternally transferred Abs to the vaccine carrier.