Biochemical and Physiological Changes in the Rat during Riboflavin Deprivation and Supplementation

Abstract

A study has been made of the time course of changes in organ weight, organ protein content and concentration, and the succinic dehydrogenase activity for the heart, kidneys and liver of the rat during the development of riboflavin deficiency and during the recovery process. The rate and quantity of ¹⁴C-2-riboflavin uptake by the mitochondria and the specific incorporation of the vitamin into the protein of succinic dehydrogenase were studied in the liver during the recovery process. Though the deficiency caused a fall of approximately 50% in the enzyme activity of the liver of the deficient group, the restriction of food consumed by the weight-controlled pairmates caused an increase in enzyme activity of about 33% in the control group. Increases in the size and protein content of the liver provide a measure of protection for the deficient animal. The development of riboflavin deficiency appears to result in the production of increased numbers of liver mitochondria of reduced protein and flavin content. Recovery from the deficiency involves an extremely rapid uptake of protein by the mitochondria and a slower but steady incorporation of riboflavin by the protein of the enzyme. The heart is insensitive and the kidney relatively insensitive to riboflavin deprivation or supplementation.