Fig. 3. Effect of exogenously added serine protease inhibitors on adipocyte conversion. Post-confluent 3T3-L1 cells were incubated for 24 hours before and 48 hours during the adipogenic induction in medium containing 1-AT, 1-PDX or dec-RVKR-CMK. They were then cultured for 5 days in normal medium and stained with Oil Red O on day 7 to assess conversion. (A) Staining was reduced in cells treated with 8 µM 1-PDX, but not in those treated with 1-AT. (B) Treatment with dec-RVKR-CMK reduced the staining in a concentration-dependent manner. The same results were obtained in four separate experiments. (C) By general cellular morphology, blockage of adipocyte conversion was partial at 20 µM dec-RVKR-CMK and complete at 100 µM.