[Changes in the growth rates, respiration level and mitochondrial mass of the heart during chick embryo development].

The growth of heart during the chick embryo development is accompanied by the increase in total protein content per weight unit of the organ and in the content of the actomyosin complex proteins calculated to the total heart protein. Changes in the rate of heart respiration during development are determined, mainly, by the mass of mitochondria. The growing heart at the early developmental stages is characterized by a very high rate of doubling of the mitochondrial protein mass.