INTERMEDIARY METABOLISM

Author: BARCOS MARTINEZ MONTSERRAT.
Year: 2004.
University: CÓRDOBA [www.uco.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: The study assesses the effect of red wine (VT; Montilla-Moriles) on oxidative stress and diabetes-induced estreptozotocina (STZ). To this end, female Wistar rats were used to be injected with a single dose STZ intraperitoneal route (50mg/kg) and VT diluted in their drinking water and corresponding to a dose of a drinker moderate (400 ml170 kg / day). Two groups were organized controls and three groups of diabetic animals (a group injected with STZ, another treaty with VT prior to induction with diabetic STZ and a third tried simultáneamentecon VT and STZ). After 30 days, proceeded to obt ~ nción samples of serum, plasma and urine and tissues (kidney, pancreas, liver and brain). In the samples processed know measured biochemical parameters: glucose, glycated hemoglobin, fructosamina, insulin, sodium ions and potassium, creatinine, urea, total protein, total cholesterol, HDLcolesterol and triglycerides. The parameters of oxidative stress were: lipoperóxidos, reduced glutathione and the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase. In animals injected with STZ found significant increases in the levels of glucose, glycated hemoglobin and fructosamina well as a significant decrease in plasma insulin, which demonstrated the establishment of a diabetic condition also was accompanied by significant increases in glycosuria, proteinuria and microalbuminuria . It was observed alteration in the profile lipídico with increased levels of serum cholesterol and atherogenic index. The table of oxidative stress in these animals was evidenced by significant increases in levels of lipoperoxidación well as a decrease in the content of antioxidant enzymes and reduced glutathione. The administration VT prior to induction diabetic improved both the diabetic state as oxidative stress by increasing insulin levels and antioxidant enzymes and improved lipid profile. VT provided simultaneously with the induction of diabetes by STZ was not as effective on the table diabetic but on oxidative stress.

Author: BELTRAN ARCAS MARTA.
Year: 2005.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE BIOLOGÍA.
Place of preparation: FACULTAD DE BIOLOGÍA.

Summary: The limitation of fishmeal has stimulated research of plant resources as alternative sources for the cultivation of carnivorous species. In general, high percentages of plant sources typically involve a decrease is associated, among other reasons, to the lower quality of vegetable protein compared to animal protein. Des physiological point of view, there is a close connection between the content of amino acids in the diet (especially essential amino acids), amino acid-free tissues, metabolism in these tissues and the use of amino acids to synthesize proteins. The overall objective of this thesis was to study the effect of substitution on the usability of the protein in the diet. For this study, diets with different percentage of replacement were marked with stable isotopes (13C and 15N), and followed up post (11 and 24 hours) of the protein in the diet. It discussed the incorporation of marking in the main components of tissues (muscle, liver, viscera), as well as plasma free amino acid and muscle. The incorporation of markers from the protein diet in the tissues and its major components, as well as the free amino acid and muscle plasma shows that golden trout and can be replaced by 50% of fishmeal unaltered the use of the protein in the diet. The allowance of 75% substitution resulted in trout greater oxidation of the protein in the diet, having an impact on growth. However, the distribution pattern of markers in the main components of the tissue was similar to the control of the situation. In contrast, 100% substitution caused an increase in this kind of recycling of the amino acids from muscle, a decrease of the relationship essential amino acids / non-essential amino acids in plasma and muscle, as well as an activation of the gluconeogéneiss liver. Moreover, the monitoring of carbohydrates in the diet 100% vegetable (by marking with almidón- 13C) revealed the low availability of the latter. In gold, a 75% substitution caused, as in trout, increased oxidation of the protein in the diet. In this species, the availability of the amino acids in the diet decreased when their home was 100% vegetable, which caused an increase recycling protein in muscle, as evidenced by the higher isotopic enrichment of alanine, apparatus and proline, and declining the relationship essential or non-essential. However, the golden showed no problems delos carbohydrate digestion and absorption of dietary 100% vegetable. The technique of marking with stable isotopes has allowed not only do these studies without problems of environmental pollution and staff, but also the study of isotopic fractionation of 15N has proved a useful tool for determining protein recycling. Moreover, our studies show that the 15N may be a good marker of origin of the protein in the diet.

Author: SIERRA LOPEZ ALEJANDRA.
Year: 2005.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: INSTITUTO DE INVESTIGACIONES BIOMEDICAS "ALBERTO SOLS".
Place of preparation: UNIVERSIDAD NACIONAL DE EDUCACIÓN A DISTANCIA - INSTITUTO DE INVESTIGACIONES BIOMEDICAS.

Summary: This thesis metabolic compartmentalization of glutamate and lactate in the brain intact adult rat and in primary cultures of astrocytes and neurons, using a new methodology based on double marking dynamic brain metabolites with 13C and 2H detected using Nuclear Magnetic Resonance 13C high resolution. For the investigation of the compartmentalization of glutamate in the brain intact rat adult male Wistar rats were used adult (150-180g, n = 72). The animals received food ad libitum and 2H2O to 50% as drinking water for nine days. On the last day, animals were infused with (1-13C) glucose (8 umol.min-1. 100 g-1) or (2-13C) acetate (24 umol.min-1.100 g-1) at intervals growing of 5,10,15,30,60 and 90 minutes. At the end of the infusion, the brain extracts were prepared from acid-soluble metabolites and their spectra were analyzed (13C, 2H) TMN which allowed study dynamically exchanges 1H by 2H in various carbons glutamate and glutamine due to the occurrence isotopic effects. The administration of water deuterada decreased velocity incorporation of 13C in the various carbons of glutamate and glutamine. The kinetic analysis of exchange 1H by 2H in carbon C3 (2-13C) glutamate and glutamine, reveals isotropómeros mono and bideutera-dos (3R) or (3S) - (2-13C, 3-2H ) and (2-13C, 3.3 '-2H2)), with production cytosolic or mitochondrial respectively. The adjustment to a mathematical model of minimal brain metabolism were established: 1 - The existence of more than one intracellular pool of glutamate. 2-That the deuteración in H3 pro-R inhibits deuteración in H3 pro-S. 3-To more than 80% of glutamate produced in the cycle tricarboxílico neuronal or glial involved in the cycle glutamato-glutamina. 4-That the cycle tricarboxílico glial presents speeds deuteración faster than the neuronal. To study the compartmentalization of lactate, were incubated primary cultures of astrocytes and neurons with (3-13C) lactate, glucose (1-13C) or acetate (2-13C) in the presence and absence of 2H2O to 50% by analyzing ( 13 C 2H) NMR Media incubation at times rising up to 48 hours. The spectra show resonances lactate C3 with a profile of isotopic complex movements, which shows that astrocytes lso used simultaneously glucolisis and the cycle tricarboxílico to get your energy. The spectra of (13C, 2H) NMR obtained during incubaciones of neurons and astrocytes with lactate (3-13C) show the resonances of the original (3-13C) and lactate (3-13C, 2-2H) lactate in the recycling cytosol by the action of the lactate dehydrogenase. A mathematical modeling of this process shows that astrocytes mainly recycled lactate, while neurons make it the Pyruvate. These resutlados provide a new interpretation to classical notions of metabolic coupling between neurons and astrocytes. We propose here that the metabolic and functional coupling between these cells occurs through a system of shuttles transcelular equivalent reduction in the form of lactate and Pyruvate, similar to the intracellular redox state couples from cytosol and mitochondria in neural cells.