In vivo enzymatic activity of acetylCoA synthetase in skeletal muscle revealed by 13C turnover from hyperpolarized [1-13C]acetate to [1-13C]acetylcarnitine

BACKGROUND: Acetate metabolism in skeletal muscle is regulated by acetylCoA synthetase (ACS). The main function of ACS is to provide cells with acetylCoA, a key molecule for numerous metabolic pathways including fatty acid and cholesterol synthesis and the Krebs cycle. METHODS: Hyperpolarized [1-(13)C]acetate prepared via dissolution dynamic nuclear polarization was injected intravenously at different concentrations into rats. The (13)C magnetic resonance signals of [1-(13)C]acetate and [1-(13)C]acetylcarnitine were recorded in vivo for 1min. The kinetic rate constants related to the transformation of acetate into acetylcarnitine were deduced from the 3s time resolution measurements using two approaches, either mathematical modeling or relative metabolite ratios. RESULTS: Although separated by two biochemical transformations, a kinetic analysis of the (13)C label flow from [1-(13)C]acetate to [1-(13)C]acetylcarnitine led to a unique determination of the activity of ACS. The in vivo Michaelis constants for ACS were KM=0.35±0.13mM and Vmax=0.199±0.031μmol/g/min. CONCLUSIONS: The conversion rates from hyperpolarized acetate into acetylcarnitine were quantified in vivo and, although separated by two enzymatic reactions, these rates uniquely defined the activity of ACS. The conversion rates associated with ACS were obtained using two analytical approaches, both methods yielding similar results. GENERAL SIGNIFICANCE: This study demonstrates the feasibility of directly measuring ACS activity in vivo and, since the activity of ACS can be affected by various pathological states such as cancer or diabetes, the proposed method could be used to non-invasively probe metabolic signatures of ACS in diseased tissue.

Higher PLIN5 but not PLIN3 content in isolated skeletal muscle mitochondria following acute in vivo contraction in rat hindlimb

Contraction-mediated lipolysis increases the association of lipid droplets and mitochondria, indicating an important role in the passage of fatty acids from lipid droplets to mitochondria in skeletal muscle. PLIN3 and PLIN5 are of particular interest to the lipid droplet–mitochondria interaction because PLIN3 is able to move about within cells and PLIN5 associates with skeletal muscle mitochondria. This study primarily investigated: 1) if PLIN3 is detected in skeletal muscle mitochondrial fraction; and 2) if mitochondrial protein content of PLIN3 and/or PLIN5 changes following stimulated contraction. A secondary aim was to determine if PLIN3 and PLIN5 associate and whether this changes following contraction. Male Long Evans rats (n = 21;age, 52 days; weight = 317 6 g) underwent 30 min of hindlimb stimulation (10 msec impulses, 100 Hz/3 sec at 10–20 V; train duration 100 msec). Contraction induced a ~50% reduction in intramuscular lipid content measured by oil red-O staining of red gastrocnemius muscle. Mitochondria were isolated from red gastrocnemius muscle by differential centrifugation and proteins were detected by western blotting. Mitochondrial PLIN5 content was ~1.6-fold higher following 30 min of contraction and PLIN3 content was detected in the mitochondrial fraction, and unchanged following contraction. An association between PLIN3 and PLIN5 was observed and remained unaltered following contraction. PLIN5 may play a role in mitochondria during lipolysis, which is consistent with a role in facilitating/regulating mitochondrial fatty acid oxidation. PLIN3 and PLIN5 may be working together on the lipid droplet and mitochondria during contraction-induced lipolysis.

Bacterias acidolácticas como promotoras de la digestibilidad in vitro e in vivo

Tesis (Maestría en Ciencias en Producción Animal) UANL

Efecto in vivo de diversas antracenonas diméricas sobre peroxisomas de Candida boidinii

Tesis (Maestría en Ciencias con Especialidad en Quimica Analítica Biomédica) UANL

Estudios in vivo e in vitro de la sensibilidad de actinomadura madurae frente a diversos antimicrobianos de reciente desarrollo

Tesis (Maestría en Ciencias con Especialidad en Microbiología Médica) UANL

Cambios morfológicos en la membrana plasmática del espermatozoide inducidos in vivo por secreciones de endometrio y cérvix humanos

Tesis (Maestría en Ciencias con Especialidad en Biología de la Reproducción) UANL

Actividad de caspofungina contra P. boydii: estudios in vitro e in vivo

Tesis (Maestro en Ciencias con orientación en Microbiología Médica) U.A.N.L., 2006.

¿Es el gen humano hPL-1 un pseudogen? análisis de su expresión in vivo usando técnicas de ingeniería genética y cultivo celular por Ramiro Ramírez Solís

Tesis (Maestría en Ciencias) U.A.N.L.

Determinación de la expresión in vivo e in vitro de los receptores TLR-4 y -5 durante la infección por Helicobacter pylori

Tesis (Maestría en ciencias con orientación en Microbiología médica) U.A.N.L. Facultad de Medicina, 2006.

Evaluación invitro e in vivo de las características de liberación de gabapentina a partir de biomateriales obtenidos vía sol-gel.

Tesis (Maestría en Ciencias con Orientación en Farmacia) UANL, 2011.

Efecto hipotensor e inhibición de la actividad de la enzima convertidora de angiotensina I de extractos de semillas de salvia hispánica L. in vitro e in vivo.

Tesis (Maestría en Ciencias en Nutrición) UANL, 2011.

Estudio in vivo de oseointegración en implantes dentales de Ti-6AI-4V con superficies modificadas.

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales) UANL, 2013.

Signaling of angiotensin II-induced vascular protein synthesis in conduit and resistance arteries in vivo

Affiliation: Faculté de pharmacie, Université de Montréal & Institut de recherches cliniques de Montréal

Efectos in vivo e in vitro del clofibrato y del ácido clofíbrico sobre el contenido de vimentina y desmina del citoesqueleto de miocardiocitos de rata

Tesis (Doctorado en Ciencias Biológicas) UANL

Detección e identificación de los metabolitos de la T-514 del género karwinskia in vivo e in vitro

Tesis (Doctorado en Ciencias con Especialidad en Farmacología y Toxicología) UANL