[Amino acid metabolic indices in newborn rats]. / Nekotorye pokazateli aminokislotnogo obmena u novorozhdennykh krys.

In simulated tests on rats of the 1st months of life set up for the purpose of educing causes accounting for a highly effective utilization of the milk proteins in the early post-natal perions subject to study were the amino acids metabolism rates. An investigation of the enzymes activity showed that a falling of the milk proteins utilization effectiveness proceeds against the background of an intensive inclusion of the catabolic route of the amino acids metabolism in the liver. The urea content in the urine correlated with a gradual inclusion of the enzymatic liver systems partaking in the urine formation. The amino acids metabolism with a ramified chain in the liver tissue of rats of the first days of life was found to stand low to a still greater degree than this was the case in adult animals. One of the causes responsible for a highly effective utilization of the milk proteins in the perinatal period may be due to an incomplete functioning of the catabolic route of the amino acids metabolism in the liver.

[Effective utilization of milk proteins by rats during the neonatal period]. / Effektivnost' utilizatsii belkov moloka krysami v period novorozhdennosti.

The assimilation of milk proteins in dynamics by rats during the first 23 days of their life was studied. During this time the animals were kept on a natural milk feeding and were denied the maternal one. Data on the amount of consumed protein and on an increase of the protein content in the carcass in 2- and 4-day long intervals served as a basis for determining the degree of effective utilization of protein (U) by rats. It is shown that the degree of the food protein, while remaining at a high level, experienced certain changes. It is possible to distinguish three periods in the change of this value: the first--starting from birth up to 5 days, with U rising from 74,5 up to 92.1 per cent, the second period, the milk diet proper,--up to the 15th day, marked by a high value of U (approximately 93 per cent) and, finally, the third period--transitional to the ration of an adult animals--marked by a drop of U down to 67.8 per cent. The data obtained may be used in considering issues related to features specific for the processes of the protein assimilationin in the early post-natal period.