Early effects of vitamin A on protein synthesis in the epidermis of embryonic chick skin cultured in serum-containing medium

A quantitative study of the incorporation of ³H-leucine and ³⁵S-cystine by the 12-day embryonic chick epidermis during 2 days in culture in serum-containing medium, with and without added vitamin A has been made. This has shown that very soon after explantation, protein synthesis, particularly the synthesis of cyst(e)ine-rich proteins is enhanced dramatically in the epidermis cultured in the control, serum-containing medium alone. This effect is completely absent in the medium containing added vitamin A (5 IU/ml). Under these conditions ³H-leucine and ³⁵S-cystine incorporation remain relatively unchanged during the 2-day culture period.