Fig. 5. A proposed model describing extracellular substrate use in support of glycogenesis in trout muscle during recovery from exhaustive exercise. Thicker arrows indicate preferred pathways; wavy arrows indicate diffusion. LA_e, lactate of extracellular origin; LA_i, lactate of intracellular, glycolytic, origin; MCT, monocarboxylate transporter; PYR, pyruvate; LDH, lactate dehydrogenase; PDH, pryruvate dehydrogenase; GLY, glycerol; GK, glycerol kinase; G3P, glyerol 3-phosophate; DHAP, dihydroxyacetone phosphate; PA, palmitate, TCA, tricarboxylic acid cycle; CoA, coenzyme A; Ac-CoA, acetyl CoA; NAD⁺, oxidized nicotinamide-adenine dinucleotide; NADH, reduced nicotinamide-adenine dinucleotide; FAD, flavin adenine dinucleotide; FADH₂, reduced FAD. See text for details (#, reaction number).