EPIDERMAL GROWTH-FACTOR IS A POSITIVE IN-VIVO REGULATOR OF CTP- CHOLINEPHOSPHATE CYTIDYLYLTRANSFERASE

CTP:cholinephosphate cytidylyltransferase (CT) is a key enzyme require d for surfactant phosphatidylcholine synthesis, and its activity is re gulated by lung lipids. This study evaluated the effect of epidermal g rowth factor (EGF) on the phospholipid content and the expression of C T in the lung following direct in vivo administration to the newborn r at. EGF caused art increase in cytidylyltransferase activity by 58% in lung cytosol. The increase in cytosolic activity was not mediated by a corresponding increase in enzyme mass. Further, these changes in cyt idylytransferase activity were associated with a significant increase in total lung phospholipid and phosphatidylcholine content. The result s suggest that EGF may have important maturational effects on lung sur factant metabolism