[Study of protein synthesis regulating hormones in human milk]

A study was made of the content in human milk of hormones which regulate together with their specific function processes of protein assimilation and synthesis. These hormones (thyroxine, triiodothyronine, 17 beta-estradiol, prolactin, 11-hydroxycorticosteroids) were determined in the first days of lactation, in the most important period in the nutrition of a newborn and in the formation of lactation. Chromatography, radioimmunoassay and fluorometry were used. The aim of the study was to determine the levels of exogenous hormones which influence the metabolism of proteins received by a newborn. During the first 10 days of lactation the content of prolactin in human milk was 154.5-546.0 muunits/ml, that of 17 beta-estradiol 34.2-124.4 pg/ml, that of thyroxine 0.5-1.1 micrograms%, that of triiodothyronine 8.6-20.8 ng%. A possible involvement of milk hormones in the regulation of anabolic processes of a newborn as well as changes in the first 3-6 days of lactation of the prolactin and 17 beta-estradiol content in milk in connection with the regulation of the start of lactation are discussed.