Glycine absorption from the small intestines of rats after secondary infections withEimeria nieschulzi

Summary A second (challenge) infection ofEimeria nieschulzi in clinically immune rats did not produce weight gain depression but caused a decrease in the absorption of glycine from the ileum. The malabsorption due to challenge was equivalent to that caused by the primary infection which did cause weight loss.     

Absorption of glycine and proline from the small intestine of rats infected withEimeria nieschulzi

Summary The absorption of glycine and proline through the jejunum and ileum of rats with anEimeria nieschulzi infection was impaired when the amino acids were presented to the mucosal surface as either a mixture or the dipeptide, glycyl-proline.     

Post-transcriptional gene silencing of ribosomal protein S6 kinase 1 restores insulin action in leucine-treated skeletal muscle

Excessive nutrients, especially amino acids, impair insulin action on glucose metabolism in skeletal muscle. We tested the hypothesis that the branched-chain amino acid leucine reduces acute insulin action in primary myotubes via a negative feedback mechanism involving ribosomal protein S6 kinase 1 (S6K1). The effect of S6K1 on glucose metabolism was determined by applying RNA interference (siRNA). Leucine (5 mM) reduced glucose uptake and incorporation to glycogen by 13% and 22%, respectively, compared to the scramble siRNA-transfected control at the basal level. Leucine also reduced insulin-stimulated Akt phosphorylation, glucose uptake and glucose incorporation to glycogen (39%, 39% and 37%, respectively), and this reduction was restored after S6K1 silencing. Depletion of S6K1 enhanced basal glucose utilization and protected against the development of impaired insulin action, in response to excessive leucine. In conclusion, S6K1 plays an important role in the regulation of insulin action on glucose metabolism in skeletal muscle. Received 22 December 2008; received after revision 19 February 2009; accepted 23 February 2009     

High glucose-induced enzyme activity changes in cultured cell lines established from the kidneys of Chinese hamsters with aglycosuria or spontaneous glycosuria

Summary Chinese hamster kidney epithelial-like cells derived from highly inbred nondiabetic (AV) and diabetic (XA) genetic sublines were passaged in medium containing 100 or 400 mg/dl glucose. The effect of high medium glucose on the activities of 5 enzymes involved in glucose metabolism was followed and significant glucose-dependent difference was observed. The effects, however, were opposite in cells derived fromAV andXA sublines.     

Pancreatic islet β-cell deficit and glucose intolerance in rats with uninephrectomy

This study was performed to examine the effect of chronic renal impairment and renin-angiotensin system (RAS) activation induced by unilateral nephrectomy (UNX) on the development of pancreatic islet β-cell deficit and glucose intolerance. Sprague-Dawley rats were randomized into three groups: untreated UNX (n = 10), UNX treated with the angiotensin-converting enzyme inhibitor lisinopril (n = 8) and sham operation (n = 10). Blood glucose, serum insulin, renal function and histological changes of kidney and pancreas were examined 8 months postoperation. Compared with the sham rats, UNX rats developed renal impairment, insulin deficiency and glucose intolerance. Histological staining revealed an islet β-cell deficit associated with increased immunoreactivity for angiotensin and angiotensin type 1 receptor in UNX rats. Treatment with lisinopril significantly improved renal dysfunction, hyperglycemia, insulin secretion and islet RAS expression. These data suggest that chronic renal impairment and RAS activation may contribute to islet β-cell loss and glucose intolerance. RAS blockade may therefore prevent these disorders. Received 29 August 2007; received after revision 25 September 2007; accepted 27 September 2007     

Alpha-amylase inhibitor increases plasma 3-hydroxybutyric acid in food-restricted rats

The effect on energy metabolism of delayed absorption of starch by inhibition of -amylase was examined by considering levels of plasma glucose and 3-hydroxybutyric acid (3-OHBA) in rats. Addition of -amylase inhibitor (AI) to a high starch diet delayed the plasma glucose response after feeding: peak plasma glucose levels in the control group occurred 15 min after feeding, whereas in the AI group this peak did not occur until 30 min after. The total plasma glucose response was not different between the two groups. Plasma 3-OHBA levels 1 day after food restriction increased approximately five-fold in both groups. After 3 days of food restriction, the AI group maintained the same level of plasma 3-OHBA as after 1 day of food restriction, while the control group showed significantly decreased levels of 3-OHBA. After 3 days of food restriction, plasma insulin levels were significantly decreased in the AI group compared with the corresponding levels of the control group and with levels before the restriction. There was no significant difference in body weight between the two groups. These findings suggest that delayed hyperglycemia due to delayed absorption of starch following AI loading may attenuate insulin secretion, leading to altered metabolism of 3-OHBA during the delayed response to energy deficit.     

Glucose formation from methylglyoxal in hepatocytes from streptozotocin-induced diabetic mice: the effect of insulin

Acetol and methylglyoxal are intermediates of the intrahepatic metabolism of acetone leading to pyruvate formation. In hepatocytes prepared from fasted streptozotocin-induced diabetic mice, net glucose production could be measured from methylglyoxal but not from acetone or acetol. Insulin increased glucose formation from methylglyoxal in a concentration-dependent manner, whereas it was ineffective when pyruvate was used as substrate. Drug oxidation, as evidenced byp-aminophenol formation from aniline, was enhanced by methylglyoxal, and insulin proved to be stimulatory in this case as well. It is concluded that insulin might be involved in the regulation of glucose formation from methylglyoxal, but its mode of action is not yet clear.     

Oxygen consumption of the rat small intestine during infection with nematospiroides dubius

Summary Qo₂ of jejunal rings did not differ significantly between uninfected rats and rats infected for 7 days withNematospiroides dubius. Qo₂ of isolated jejunal mucosal epithelial cells was significantly greater 7 days after infection than in uninfected controls or at 29–36 days after infection.     

Glycine absorption from the small intestines of rats after secondary infections with Eimeria nieschulzi

A second (challenge) infection of Eimeria nieschulzi in clinically immune rats did not produce weight gain depression but caused a decrease in the absorption of glycine from the ileum. The malabsorption due to challenge was equivalent to that caused by the primary infection which did cause weight loss.     

Increased susceptibility ofTrypanosoma lewisi infected,or decomplemented rats toSalmonella typhimurium

Summary Rats infected withTrypanosoma lewisi or decomplemented by injection of cobra venom factor or complement activating factor of trypanosomes were found to be more susceptible to infection withSalmonella typhimurium. Decomplemented rats subsequently infected withT. lewisi developed higher blood parasitemia than did normalT. lewisi infected rats.This project is supported by the National Research Council of Canada grant A 0068 and a grant from the International Development Research Center.     

The rate of biliary cholesterol secretion in high- and low-responding rhesus monkeys

The rates of secretion of cholesterol in bile measured by an isotope ratio method were found similar in cholesterol-fed high- and low-responding rhesus monkeys. The results indicate that the failure on the part of the high-responders to increase proportionately the fecal excretion of neutral steroids to compensate for the higher absorption of cholesterol than the low-responders, as suggested earlier, is not due to a difference in the rate of biliary cholesterol secretion but must lie in some other aspect of cholesterol metabolism.     

Role of bile in intestinal absorption of203Pb in rats

Summary The author studied absorption of²⁰³Pb after administering intraduodenally²⁰³Pb eliminated with bile. The results obtained were compared with absorption of203Pb administered into the duodenum as²⁰³PbCl₂ in rats forming 2 groups, one with bile ducts cannulated, the other intact. It was found that bile played an important role in absorption of Pb from the gastrointestinal tract. Absorption of Pb²⁰³ is significantly reduced if the bile is drained off by means of a canula.     

Mg2+-ATPase defective mutant ofEscherichia coli and thiamine transport

Summary Mg²⁺-ATPase deficient mutant ofEscherichia coli showed an evident dependency of thiamine uptake on the oxidative metabolism of glucose, whereas the parent strain did not. In both cells, this uptake was completely inhibited by H⁺ conductors.Acknowledgment. We are indebted to Miss M. Abe for her excellent technical assistance.     

Two novel prolactin release-inhibiting 8α-amino-ergolines

Summary Prolactin secretion inhibition and changes in striatal dopamine metabolism in rats were compared after the administration of 8a-amino-ergoline CH 29-717 and 2 derivates. CQ 32-084 was similar to but less potent than CH 29-717. while 32-085, the 1-methyl derivative, showed delayed dopaminomimetic effects.     

Hepatic acid hydrolases of albino rats,Mastomys natalensis and albino mice duringPlasmodium berghei infection

Summary Changes in liver acid hydrolase activities during the infection of albino rats,Mastomys or mice withPlasmodium berghei are described. B-Glucosidase, B-galactosidase and N-acetyl-B-D-glucosaminidase exhibited widely different responses with acid phosphatase and cathepsin-B the least responsive and are likely to be causally related to immunity of animals.     

Einfluss der Passagegeschwindigkeit auf die Resorption von Glucose im Dünndarm der Ratte

Summary Loops of rat's small intestine have been perfused with 5% glucose solution at different flow rates. The absorption of glucose has been investigated. The results showed that, with increasing flow rates, absorption rate of glucose is also increased. Therefore contact time seems to be no limiting factor in intestinal absorption.

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Mit Unterstützung des Österr. Fonds zur Förderung der wissenschaftlichen Forschung, Projekt Nr. 650.     

Different carbon sources affect lifespan and protein redox state during Saccharomyces cerevisiae chronological ageing

In this study, a proteomic approach that combines selective labelling of proteins containing reduced cysteine residues with two-dimensional electrophoresis/mass spectrometry was used to evaluate the redox state of protein cysteines during chronological ageing in Saccharomyces cerevisiae. The procedure was developed on the grounds that biotinconjugated iodoacetamide (BIAM) specifically reacts with reduced cysteine residues. BIAM-labelled proteins can then be selectively isolated by streptavidin affinity capture. We compared cells grown on 2% glucose in the exponential phase and during chronological ageing and we found that many proteins undergo cysteine oxidation. The target proteins include enzymes involved in glucose metabolism. Both caloric restriction and growth on glycerol resulted in a decrease in the oxidative modification. Furthermore, in these conditions a reduced production of ROS and a more negative glutathione half cell redox potential were observed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 15 September 2008; received after revision 17 December 2008; accepted 06 January 2009     

MicroRNA regulation and analytical methods in cancer cell metabolism

The reprogramming of glucose metabolism from oxidative to glycolytic metabolism, known as the Warburg effect, is an anomalous characteristic of cancer cell metabolism. Recent studies have revealed a subset of microRNAs (miRNAs) that play critical roles in regulating the reprogramming of glucose metabolism in cancer cells. These miRNAs regulate cellular glucose metabolism by directly targeting multiple metabolic genes, including those encoding key glycolytic enzymes. In the first part of this review, we summarized the recent knowledge of miRNA regulation in the reprogramming of glucose metabolism in cancer cells and discussed the potential utilization of the key miRNA regulators as metabolic targets for developing new antitumor agents. Then, we summarized recent advances in methods and techniques for studying miRNA regulation in cancer cell metabolism.     

Effects of cerebral lateral,ventricular infusions of phloridzin on feeding and body weight in Gallus domesticus (L.)

Summary Contrary to earlier findings in rats, cerebral lateral ventricular infusions of 1×10^–3 M or 2×10^–3 M solutions of phloridzin at a rate of 2.5 l/min for 90 min had no significant stimulating effects on food intake and weight gain in hens and cocks. These different responses to intraventricular phloridzin might reflect a difference of sensitivity to the inhibitory action of phloridzin on glucose transport in cerebral cells or certain peculiarities of mechanisms controlling food intake in chickens.