Stimulation of HSC proliferation by standard fatty acids. LD cells were cultured on MS-5 with or without various concentrations of standard commercially available fatty acids: palmitic acid ( —  ○  — ), stearic acid (- - - ▴ - - -), oleic acid (⋅-⋅- • -⋅-⋅-), and linolenic acid ( —  □  — ). ³H-thymidine incorporation of wells was measured and compared. The data are mean ± SD. *Different from control (culture without fatty acids) (P < .05). †P < .005.