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Position and Length of Fatty Acids Strongly Affect Receptor Selectivity Pattern of Human Pancreatic Polypeptide Analogues

Pancreatic polypeptide (PP) is a satiety‐inducing gut hormone targeting predominantly the Y₄ receptor within the neuropeptide Y multiligand/multireceptor family. Palmitoylated PP‐based ligands have already been reported to exert prolonged satiety‐inducing effects in animal models. Here, we suggest that other lipidation sites and different fatty acid chain lengths may affect receptor selectivity and metabolic stability. Activity tests revealed significantly enhanced potency of long fatty acid conjugates on all four Y receptors with a preference of position 22 over 30 at Y₁, Y₂ and Y₅ receptors. Improved Y receptor selectivity was observed for two short fatty acid analogues. Moreover, [K³⁰(E‐Prop)]hPP_2?36 ( 15 ) displayed enhanced stability in blood plasma and liver homogenates. Thus, short chain lipidation of hPP at key residue 30 is a promising approach for anti‐obesity therapy because of maintained selectivity and a sixfold increased plasma half‐life.     

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Metabolic changes and net portal flux in dairy cows fed a ration containing rumen-protected fat as compared to a control diet

Feeding rumen-protected fat (RPF) is an alternative to increase energy density of the diet and therefore energy intake in dairy cows. To investigate metabolic and endocrine changes in dairy cows fed either a diet containing RPF (FD) or a control diet with an increased amount of cornstarch (SD), 3 Holstein cows (83 ± 1 d in milk) were fitted with catheters in the portal vein, a mesenteric artery, and 2 mesenteric veins. Cows were fed consecutively SD and FD for 3 wk, respectively. In FD, cornstarch [92 g/kg of dry matter (DM)] was replaced by 50 g of RPF/kg of DM (mainly C16:0 and C18:1). Tracer infusions of NaH¹³CO₃ and d-[U-¹³C₆]glucose were performed into a jugular vein to measure rate of appearance and oxidation of glucose. Arterial and portal blood samples were collected to measure concentrations of glucose, lactate, volatile fatty acids, nonesterified fatty acids, β-hydroxybutyrate, triglycerides, AA, insulin, and glucagon. Concomitantly, para-aminohippurate was infused into a mesenteric vein for measurement of portal plasma flow. Although DM intake was slightly lower in FD, protein and energy intakes were unaffected by diets. Milk and lactose yields were higher in FD than SD. Arterial plasma glucose concentration was lower with FD than SD, whereas nonesterified fatty acid and triglyceride concentrations were higher in FD. Glucagon concentration and glucagon-to-insulin ratio were both augmented by FD feeding. When feeding FD, greater milk and lactose yields, but not energy-corrected milk, were associated with elevated lipid status and higher glucagon concentrations but occurred despite lower plasma glucose concentration and were not linked with changes in whole body glucose rate of appearance. This study suggests a glucose-sparing effect allowing an enhanced lactose synthesis when feeding RPF.     

Zur Frage der Bewertung von Labor-Versuchsergebnissen über die Basidiomyceten-Resistenz der Holzarten

Bavendamm first evaluated the resistance against basidiomycetes using an equation: He compared the weight loss expressed as percentage of the wood species to be tested with that of a well-known home grown species. This suggestion was adopted by v. Hof. A critical assessment of his papers led to the proposal of a new definition of v. Hof's equation. Here the influencing parameters of test methods and test fungi are eliminated which leaves the typical properties of the wood species for evaluation. This makes it possible to compare the results of different laboratory tests.     

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Bundesforschungsanstalt für Forst- und Holzwirtschaft,Reinbek

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Zur Synthese von 3-Amino-pyrrolen durch Thorpe-Ziegler-Cyclisierung

On the Synthesis of 3-Amino-pyrroles by Thorpe-Ziegler-Cyclization N-Aryl and alkylaminomethylene cyanacetic acid derivatives 1 react with α-halogencarbonyl compounds 2 in the presence of potassium carbonate/sodium ethoxide to yield the substituted 3-amino-pyrroles 6. Using the same principle of cyclization pyrrole derivatives 6 can also be obtained by reaction of β-chloro- and β-alkoxymethylenemalononitriles 4 with β-aminocarbonyl compounds 5. From the malononitrile derivatives 1 containing the methylthio group in the β-position, and α-halogen ketones 7 , the 2-dicyanomethylene oxazolines 8 arise which undergo alkoholysis by treatment with sodium alkoxide to form the 3-amino-5-alkoxy-pyrrole derivatives 9 .