Wenying Ye

Document Type

Thesis - University Access Only

Award Date

1994

Degree Name

Master of Science (MS)

Department / School

Chemistry

First Advisor

Douglas C. McFarland

Abstract

Platelet-Derived Growth Factor (PDGF) is a potent mitogenic component of serum which is released from platelets during the clotting of blood (Balk, 1971). Two homodimeric forms of PDGF (AA and BB) and one heterodimeric form (AB) linked by disulfide bonds with molecular weights of about 30 KDa (Heldin and Westermark, 1990) have been purified from platelets and transformed cells (Bowen-Pope et al., 1989). There are two receptor proteins (α and β) which dimerize to form three receptor combinations (αα, αβ and ββ) having different binding specificities for the three PDGF isoforms (Seifert et al., 1989). In the present study, the role of PDGF isofmms on the proliferation of turkey skeletal muscle cells was examined using clonal-derived turkey myogenic cells with a specific serum-free medium (McFarland et al., 1991b). Three pairs of cell lines were selected for this research to compare characteristics of myogenic cells from different cell stages, genetic origins or muscle type. While BB and AB isoforms enhanced proliferation of the satellite cells (SC) and embryonic myoblasts (EM), the AA isoform had no effect. SC and EM administered FGF and PDGF were more responsive to the BB isoform than to the AB isoform. The BB isoform was also a more potent mitogen than the AB isoform for SC derived from domestic Nicholas (DN) and wild Meniam's (WM) turkeys. However, WM cells were more responsive to PDGF than DN cells. The interaction of PDGF-BB with receptors on these model systems was examined using competitive binding assays with [125I]PDGF. The PDGF displacement curves were similar (P≥.05) between SC and EM, DN and WM, and pectoralis major (PM) and biceps femoris (BF). Scatchard analysis (McPherson, 1985) on all cell populations were linear, suggesting the presence of a single class of PDGF receptors on these six cell lines. The receptor dissociation constants (Kds) between cell types within each comparison were not significantly different (P≥0.05), suggesting similar receptor affinities for PDGF-BB. Additionally, receptor numbers were similar between SC and EM and between DN and WM satellite cells. However, receptor numbers were 40% higher in BF cells compared to PM cells. The results suggest that PDGF may be an important factor in turkey skeletal muscle development.

Library of Congress Subject Headings

Turkeys -- Growth
Platelet-derived growth factor
Muscle cells

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright