Tissue factor in cultured cells: metabolic control

Tissue factor content of WISH amnion cells in spinner culture increases 3- to 10-fold within 12 hours after subculture, then declines to a basal level within 30 to 50 hours. Maximal development of activity requires fresh serum and fresh medium. When added at the time of subculture, actinomycin D and cycloheximide completely inhibit development of coagulant activity; when added several hours after transfer, these inhibitors suppress the development but do not affect the disappearance of activity. Of the oxidative phosphorylation inhibitors tested, dinitrophenol had no effect whereas carbonyl cyanide m-chlorophenylhydrazone inhibited the activity increase but did not alter the decline. The kinetics of development and decay are similar over a pH range of 6.7 to 7.6 and with fetal calf serum concentration between 5 and 30 per cent. At pH 6.7 or in 30 per cent fetal calf serum, cell division did not occur. 3H-leucine and 35SO4= incorporation into the cell surface coat did not change appreciably during the burst of coagulant activity nor did the levels of naphthylamidase or alkaline phosphatase; 3H-thymidine incorporation reached a peak within 2 hours of the tissue factor maximum.