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The Transforming Growth Factor‐Betas: Past, Present, and Future

The present volume on transforming growth factor-betas (TGF-0s) provides a summation of the current excitement in research on this family of peptides. This excitement is largely the result of the realization that the study of TGF-p in its multiple forms is germane to almost any topic in the entire field of biomedical research. E F p indeed is the prototypical multifunctional peptide growth factor. It is now recognized that essentially all cells may synthesize one or another isoform of TGF-P and that almost all normal cells possess functional membrane-bound receptors for members of this family of peptides. Thus, TGF-P can act by both autocrine and paracrine mechanisms to regulate the behavior of almost every cell in the mammalian organism. Depending on the particular cellular context of its action, TGF-p may act as a signal at certain times to enhance cellular proliferation, at other times to inhibit cellular proliferation, and in still other circumstances to modulate numerous other activities of cells that relate to their differentiated state, but are unrelated to DNA synthesis. In the present article, we will give a short historical introduction to the development of TGF-p research, then briefly summarize the present range of E F p studies, and finally conclude with some speculations about the directions of future research on EF-p .