Local production of SCF in the HF microenvironment. (A) Triplicate total RNA samples isolated from vibrissal follicles were subjected to real-time RT-PCR analysis for β-actin and SCF. The curves represent relative fluorescence intensities of the resulting PCR products after indicated cycles of amplification. Inserts indicate PCR products after 50 cycles after ethidium bromide staining. (B) Vibrissal follicle samples (•) or HF-derived CD45^– fibroblasts (○) were cultured for the indicated periods and culture supernatants were then examined for SCF by ELISA. Data shown are the means ± SDs from triplicate cultures. Results shown in this figure are representative of 3 (A) or 2 (B) independent experiments.