Rôle du foie dans le métabolisme des nutriments en nutrition artificielle

The liver is a prominent organ in nutritional homeostasis. Due to unique metabolic properties, it plays a main role in the metabolism of the three macronutrients ‘as well as the micronutrients’ (vitamins and minerals) storage. Although it represents only 2.5% of the body mass, it consumes 20% of total resting energy expenditure and a similar percentage of the amino acid mixture absorbed via the gut during and after a meal. Due to a peculiar vascularization (portal vein, the entire gastrointestinal venous flux is directed towards the liver with all hydrosoluble nutrients, only water-unsoluble lipids being excluded from this obligatory ‘first-pass mechanism’). Since it is the location for glycogen storage, VLDL synthesis and ketogenesis, the liver is crucial in the fed-to-fasted metabolic alternation. While fat is not physiologically stored in the liver, it is a very important organ in lipid metabolism. Except immunoglobulins, all plasma proteins are synthetised by the liver together with the constitutive proteins, explaining that it is a very powerful organ for protein synthesis. Finally, due to a very active amino acid metabolism, the liver can reshape the amino acid-mixture coming from the gut in the absorptive state. Such a phenomenon has a major implication in the nutritional physiology of amino acid metabolism according to the route: enteral or parenteral. Indeed, in the latter case the remodelling by the liver does not occurs.     

New natural sesquiterpenes as modulators of daunomycin resistance in a multidrug-resistant Leishmania tropica line.

The effects produced by nine dihydro-beta-agarofuran sesquiterpenes isolated from Crossopetalum tonduzii (1-8) and Maytenus macrocarpa (9) (Celastraceae) on the reversion of the resistant phenotype on a multidrug-resistant Leishmania line and their binding to recombinant C-terminal nucleotide-binding domain of Leishmania P-glycoprotein-like transporter were studied. The structures of the new compounds (1-5) were elucidated by spectroscopic methods, including (1)H-(13)C heteronuclear correlation (HMQC), long-range correlation spectra with inversal detection (HMBC), ROESY experiments, and chemical correlations. The absolute configuration of one of them (1) was determined by CD studies. The structure-activity relationship is discussed.