98 research outputs found
Lipid accumulation in isolated perfused rat hearts has no apparent effect on mechanical function or energy metabolism as measured by 31P NMR.
Male Sprague-Dawley rats were fed diets that contained 20% by weight soybean oil or rapeseed oil (21% and 43% erucic acid) for 7 days. The rapeseed oil diets increased the cardiac triacylglycerol content 5-fold and 25-fold, respectively, above control values. Hearts were removed from the animals and perfused with modified Krebs-Henseleit buffer at 37 degrees C. The calculated rate-pressure product was used as a measure of contractile function. 31P NMR spectra were acquired throughout a protocol that consisted of 12 min control perfusion, followed by 12 min perfusion with 20 microM isoproterenol, 12 min washout, 12 min total global ischemia, and 28 min reperfusion. The steady state levels of creatine phosphate, ATP, intracellular pH, contractile function, and the free energy of ATP hydrolysis (delta GATP) were determined for all three groups of hearts. Isoproterenol more than doubled the rate-pressure product of the hearts on all diets and decreased the concentrations of creatine phosphate and ATP with a concomitant rise in Pi. After global ischemia, creatine phosphate levels recovered fully, ATP levels remained low, and most hearts developed ventricular fibrillation. Changes in intracellular pH were the same for all groups: pH was 7.1 throughout the equilibration and isoproterenol perfusion period, decreased to pH approximately 6.4 during ischemia, and returned to 7.0 during reperfusion. The results indicate that the fat accumulation that occurs in the hearts of rats fed diets rich in high erucic acid rapeseed oil does not interfere with the cardiac high energy phosphate metabolism or contractile function.(ABSTRACT TRUNCATED AT 250 WORDS
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Valores Energéticos do Milheto, do Milho e Subprodutos do Milho, Determinados com Frangos de Corte e Galos Adultos
Research Note: Pellet Binder and Steam Pelleting as Nitrogen-Corrected True Metabolizable Energy Contributors: An Example of the Statistics Used to Evaluate a Component of a Mixture
Standard Errors of Nitrogen-Corrected True Metabolizable Energy Estimates: Effects of Pooling Excreta Samples and Ignoring Among-Control Bird Variation
A Comparison of the Amounts of Energy and Nitrogen Voided as Excreta by Cockerels Housed over Trays or Fitted with Harnesses and Plastic Collection Bags
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