Effects of defective in vivo synthesis of mitochondrial proteins on cellular biochemistry and physiology of malnourished rats

• Published in: Annals of nutrition and metabolism Vol. 34; no. 3; p. 147
• Main Authors: Olowookere, J O, Olorunsogo, O O, Malomo, S O
• Format: Journal Article
• Language: English
• Published: Switzerland 1990
• Subjects: Animals; Male; Membrane Proteins - biosynthesis; Mitochondria - metabolism; Nutrition Disorders - metabolism; Oxidative Phosphorylation; Protein-Energy Malnutrition - metabolism; Rats; Rats, Inbred Strains
• ISSN: 0250-6807
• DOI: 10.1159/000177581

Investigations were carried out to find the biochemical and bioenergetic implications of a defective in vivo synthesis of mitochondrial proteins during dietary-protein depletion. 3.4% dietary protein was fed to 21-day-old weanling rats for 30 days (experimental), while 21.0% dietary protein was fed to controls. A close simulation of marasmic-kwashiorkor syndrome was obtained in the experimental group. Rat liver mitochondria were isolated, and the functional and structural integrity was determined using biochemical standard parameters. Results show that the respiratory control ratio (RCR) is reduced by 50% in the experimental group, using any of the pyruvate/malate, beta-hydroxybutyrate or succinate as substrate. The effects of storage at 0 degree C were more pronounced in mitochondria from protein-depleted rats as these mitochondria are more leaky to protons (H+); hence they are defective in carrying out chemiosmotic oxidative phosphorylation. There is a drastic reduction in the basal ATPase and cytochrome oxidase activities with low ATP production and a decline in energy expenditure. This led to serious bioenergetic consequences culminating in heavy dependence on glycolysis and other biochemical aberrations.