Regulatory effects of IL-1α (10 ng/mL) on the expression of SCF mRNA and c-kit mRNA in HUVEC. Cells were stimulated with IL-1α over a time period from 0, 2, 4, 6, 8, 12, and 24 hours. Total cellular RNA was extracted and studied for regulation of both c-kit mRNA expression and SCF mRNA expression using Northern blot analysis. c-kit–specific mRNA could be detected at 5.5 kb (arrow); two SCF-specific transcripts are indicated by arrows (6.5 kb and 4.3 kb).The membrane was then rehybridized with a probe for GAPDH.