title: Threonine-deficient diets induced changes in hepatic bioenergetics.
abstract: Diets deficient in an indispensable amino acid are known to suppress food intake in rats. Few studies were focused at understanding how amino acid-deficient diets may elicit biochemical changes at the mitochondrial level. The goal of this study was to evaluate mitochondrial function in rats fed diets with 0.00, 0.18, 0.36, and 0.88% threonine (Thr) (set at 0, 30, 60, and 140% of Thr requirement for growth). Here, it is described for the first time that Thr-deficient diets induce a specific uncoupling of mitochondria in liver, especially with NADH-linked substrates, not observed in heart (except for Thr-devoid diet). The advantage of this situation would be to provide ATP to support growth and maintenance when high-quality protein food (or wealth of high-quality food in general) is available, whereas Thr-deficient diets (or deficient-quality protein food) promote the opposite, increasing mitochondrial uncoupling in liver. The uncoupling with NADH substrates would favor the use of nutrients as energy sources with higher FADH-to-NADH ratios, such as fat, minimizing the first irreversible NADH-dependent catabolism of many amino acids, including Thr, thus enhancing the use of the limiting amino acid for protein synthesis when a low quality protein source is available.
authors.affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, USA.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Ross-Inta
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Zhang
authors.forename: Andrew
authors.initials: A
authors.lastname: Almendares
authors.forename: Cecilia
authors.initials: C
authors.lastname: Giulivi
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D004195:Disease Models, Animal; D004435:Eating; D004734:Energy Metabolism; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008929:Mitochondria, Heart / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010085:Oxidative Phosphorylation; D011488:Protein Deficiency / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013912:Threonine / Q000008:administration & dosage / Q000172:deficiency*; D013997:Time Factors
chemical_list: D004044:Dietary Proteins; D009243:NAD; D005182:Flavin-Adenine Dinucleotide; D013912:Threonine; D000255:Adenosine Triphosphate