FIBROBLAST GROWTH-FACTOR, EPIDERMAL GROWTH-FACTOR, INSULIN-LIKE GROWTH-FACTORS, AND PLATELET-DERIVED GROWTH FACTOR-BB STIMULATE PROLIFERATION OF CLONALLY DERIVED PORCINE MYOGENIC SATELLITE CELLS

Clonally derived cultures of porcine skeletal muscle satellite cells w ere developed. The mitogenic effects of basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin-like growth factors (I GF-I and -II), and platelet-derived growth factors (PDGF-AA and -BB) w ere examined. Individually, bFGF, IGFs, and PDGF-BB stimulated prolife ration of porcine satellite cells grown in basal serum-free medium or Minimum Essential Medium containing 2% fetal bovine serum (MEM-2% FBS) . EGF stimulated proliferation in MEM-2% FBS, but neither EGF nor PDGF -AA were mitogenic when added to serum-free medium. The interactions a mong bFGF, EGF, IGF-1, and PDGF-BB were examined in serum-free medium, using growth factor concentrations shown in dose-response experiments to induce maximal proliferative responses (10 ng/ml bFGF, EGF and PDG F-BB, and 50 ng/ml IGF-I). The combination of bFGF and IGF-I dramatica lly increased proliferation, and IGF-I also synergized with EGF to inc rease proliferation. EGF, IGF-I, and bFGF interacted with PDGF-BB to s timulate proliferation. With the exception of EGF and bFGF, combinatio ns of two growth factors typically resulted in greater than additive r esponses. Simultaneous exposure of satellite cells to bFGF, PDGF-BB, E GF, and IGF-I produced a fivefold increase in DNA compared to cells gr own in basal serum-free medium. Elimination of EGF did not reduce the mitogenic response, yet removal of IGF-1, bFGF, or PDGF-BB reduced pro liferation by approximately 40, 20, and 10 %, respectively. These mito gens are likely physiological regulators of porcine satellite cell act ivity. (C) 1993 Wiley-Liss, Inc.