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Summary of Session IV Growth Hormone Action

  • A. Joseph D’Ercole
Part of the Serono Symposia, USA book series (SERONOSYMP)

Abstract

How growth hormone (GH) exerts its growth-promoting actions has been a subject of controversy. The debate has centered on whether these effects of GH result from direct action on target cells or are mediated indirectly by stimulation of production of somatomedins/insulin-like growth factors (Sm/IGFs). Resolution of this question now appears to be coming into sight. A variety of lines of evidence suggest that both GH and the Sm/IGFs act sequentially and in concert to promote growth. While it has not been shown to stimulate cellular proliferation directly (erythroid cell being a possible exception), GH causes differentiation of myoblast and preadipocyte cell lines (1). Once differentiated, these cells proliferate readily in response to somatomedin-C/insulin-like growth factor I (SmC/IGF-I) (2). The data presented by Dr. Isaksson and colleagues in this volume strengthen the belief that the sequential action of GH and SmC/IGF-I may be operative also in the growth of chondrocytes. They have shown that GH increases the abundance of SmC/IGF-I messenger RNA (mRNA) and the appearance of SmC/IGF-I immunoreactive cells in the epiphyseal proliferative zone of hypophysectomized rat cartilage. It is likely that SmC/IGF-I then stimulates cellular proliferation and expansion of the epiphysis. SmC/IGF-I and IGF-II have well-documented mitogenic effects on a wide variety of cultured cells. When administered in vivo to hypophysectomized rats, Sm/IGFs can reproduce GH’s growth-promoting actions (see reviews by Doctors Froesch and Hizuka and their co-workers). While SmC/IGF-I seems to mediate the stimulatory effect of GH cellular proliferation, GH probably acts without SmC/IGF-I to stimulate cellular differentiation and a variety of other metabolic events (the latter are reviewed by Dr. Goodman and co-workers).

Keywords

Growth Hormone Immunoreactive Cell Growth Hormone Receptor Erythroid Cell Growth Hormone Action 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

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    D’Ercole AJ, Stiles AD, Underwood LE. Tissue concentrations of somatomedin-C: further evidence for multiple sites of synthesis and paracrine or autocrine mechanisms of action. Proc Natl Acad Sci USA 1984; 81: 935–9.PubMedCrossRefGoogle Scholar
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Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • A. Joseph D’Ercole
    • 1
  1. 1.Chapel Hill School of MedicineThe University of North CarolinaChapel HillUSA

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