EFFECTS OF EGTAZIC ACID AND CALCIMYCIN ON SYNTHESIS OF DNA AND COLLAGEN IN CULTURED HUMAN LUNG FIBROBLASTS

AIM: To study the effects of egtazic acid (EA) and calcimycin (Cal) on the synthesis of DNA and collagen in cultured human lung fibroblasts (HLF). METHODS: The synthesis of DNA and collagen was determined by me asuring the incorporation of [H-3]TdR and [H-3]proline of HLF respecti vely. RESULTS: The collagen synthesis increased markedly 24 h after ex posure to both EA (0.05 - 4 mmol . L(-1)) and Cal (0.25 - 20 mu mol . L(-1)), and that there was no obvious change in DNA synthesis. After 3 6 - 48-h exposure, both DNA and collagen syntheses decreased in the gr oups of EA (1, 2, and 4 mmol . L(-1)); the DNA synthesis was also supp ressed in Cal groups in a concentration-dependent manner, whereas coll agen synthesis decreased only in Cal (10 and 20 mu mol . L(-1)). CONCL USION: Extracellular Ca2+ influx into fibroblasts increased collagen p roduction, However, the DNA synthesis was suppressed when the cytosoli c Ca2+ was too high or too low.