Effects of chlorpromazine and actinomycin D on uptake and incorporation of certain amino acids, hypoxanthine and thymidine in cultures of human skin epithelial cells.

Abstract Chlorpromazine (CPZ) 1· × 10 −4 M inhibited the uptake and incorporation of alanine (25 and 3 per cent of controls respectively), the uptake of α-aminoisobutyric acid (AIB, 39 per cent of controls) and the uptake and incorporation of hypoxanthine (36 and 44 per cent of controls) into acid-soluble and insoluble fractions of human skin epithelial cells (HE cells, NCTC 2544) grown in culture. The uptake of phenylalanine and 1-aminocyclopentane-1-carboxylic acid (cycloleucine) was not inhibited by CPZ in the same dose range, but CPZ above 10 −5 M inhibited the incorporation of phenylalanine into acid-insoluble material with 50 per cent inhibition at 6·5 × 10 −5 M. Actinomycin D stimulated the uptake of thymidine into the acid-soluble fraction of the HE-cells, 5·0 μg/ml increased the uptake to 160 per cent of the controls. The uptake of hypoxanthine was inhibited by actinomycin D, 5·0 μg/ml reduced the uptake to 67 per cent of controls. Actinomycin D did not alter the uptake of AIB or cycloleucine.