Thiazolidinedione induces the adipose differentiation of fibroblast-like cells resident within bovine skeletal muscle

To investigate the role of peroxisome proliferator-activated receptor gamma (PPAR gamma) in adipocyte formation within the skeletal muscle of beef cattle, fibroblast-like cells were isolated from the longissimus muscle of cattle and cultured with activators of murine PPAR gamma. A thiazolidinedione T-174, which is a specific ligand for PPAR gamma, stimulated adipose differentiation (evaluated by counting differentiated adipocytes under microscopic observation) in a dose-dependent fashion. A peroxisome proliferator Wy14,643 which strongly activates the a isoform of murine PPAR also stimulated differentiation but its potency was weaker than that of T-174. Unexpectedly, 15-deoxy-Delta(12,14)-prostaglandin J(2), which is believed to be an endogenous ligand for PPAR gamma, could not induce adipose differentiation in doses which have been found to be effective on rodent cells. Immunoblotting analysis confirmed the significant expression of PPAR gamma protein in fibroblast-like cell cultures prepared from bovine skeletal muscle. In conclusion, bovine skeletal muscle contains adipose precursor cells expressing functionally active PPAR gamma. (C) 1998 Academic Press.