[Blood amino acid composition of poikilothermic vertebrate under prolonged starvation].

Free amino acids in the blood plasma of lamprey (Lampetra fluviatilis) and frog (Rana temporaria) have been determined quantitatively for the periods of deprivation of the exogenous feed. The lamprey's total amino acid pool increased by 74% from November to April and reached the lower limit known for the mammals. The amount of free amino acids in frogs decreased by 40% in the spring as compared with the autumn values. The difference is accounted for by certain features of the living cycles of these animals. A more energetic proteolysis in the lamprey tissues as compared with that in the frog tissues has been confirmed by quantitative determining of leucine, isoleucine and valine in the blood of these animals. Apart from the above, alanine, glycine, lysine, threonine and, in certain periods, tyrosine have been found to be quantitatively significant in the plasma of both animal species. The composition and proportion of the amino acids in blood plasma of these animals are due to specific features of their metabolism and connected with the energy state of the liver cells under starvation.