title: Subcellular origin of the surface fluorescence of reduced nicotinamide nucleotides in the isolated perfused rat heart.
abstract: Surface fluorometric measurements and indicator metabolite determinations in the isolated perfused rat heart showed that the NADH + NADPH fluorescence of the intact tissue originates largely from the mitochondria. The redox potential of the lactate dehydrogenase system calculated from the endogenous lactate/pyruvate ratios was closely similar to that of the glycerol-3-phosphate dehydrogenase system calculated from the concentrations of glycerol-3-phosphate and dihydroxyacetone phosphate in the tissue. Thus, in contrast to the liver, the cytosolic redox state of the NADH/NAD+ system in isolated perfused heart oxidizing external glucose or fatty acid is not amenable to optical monitoring, but can be assessed from the state of the lactate dehydrogenase or glycerol-3-phosphate dehydrogenase systems.
mesh_terms: D000818:Animals; D005260:Female; D005453:Fluorescence; D005470:Fluorometry; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000201:enzymology / Q000378:metabolism; D009243:NAD / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D009536:Niacinamide / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D009243:NAD; D009536:Niacinamide; D009249:NADP; D005993:Glycerolphosphate Dehydrogenase; D007770:L-Lactate Dehydrogenase