[Effect of calciferol-protein deficiency on the metabolism of bone collagen]

Growing rats received rations with separate and combined deficiencies of vitamin D, protein and certain essential amino acids, during 60 days. An increment was recorded in the total amount of collagen in the tubular bones at the expense of its mature, insoluble fraction, in the presence of a decreased content of salt- and acid-soluble fractions of this protein. These shifts were more manifest in combined calciferol-protein deficiency. Disorders in the correlation of collagen biosynthesis, maturation and degradation processes were responsible for these shifts, which was confirmed by the corresponding changes in the rate of 4C-glycine-1 build up in proteins of the bone tissue organic matrix and in the intensity of hydroxyproline urinary excretion.