Somatomedin-C as a fetal growth promoting factor and amino acid composition of cord blood in Japanese neonates.

A study was undertaken to determine the relationship of somatomedin-C as a growth promoting factor to amino acid composition of umbilical venous blood in relationship to fetal growth. In full term pregnancy somatomedin-C from cases with appropriate fetal growth was greater than those with fetal growth retardation. Within the physical parameters of the neonate only birth weight of appropriate for date babies had significant positive relationship to somatomedin-C in cord blood. Of the 40 amino acids and their analogues, significant positive correlations were found for glutamine, prolin, asparagin, methionin, isoleucin and ethanolamine in relation to the level of somatomedin-C, while a significant negative correlation was found between tryptophane and somatomedin-C of appropriate for date babies. In cases with fetal growth retardation, the evaluation of amino acid-somatomedin-C relationship revealed that glutamine demonstrated a significant positive correlation and tryptophane demonstrated a significant negative correlation. While many details of these relationships are not clear, the results of this report lead us to speculate that somatomedin-C as a growth promoting factor in the fetus has some relationship to metabolites of tryptophane, for example serotonine and or melatonine, in regulating fetal growth in utero.