Document Detail

Prolactin isoform 2 as an autocrine growth factor for GH3 cells.
MedLine Citation:
PMID:  1639009     Owner:  NLM     Status:  MEDLINE    
Because PRL has growth factor activities in several tissues, we have asked whether it also has autocrine growth factor activity in pituitary GH3 cells. GH3 cells were grown at increasing densities in the presence or absence of antirat PRL (polyclonal and monoclonal) or nonspecific antibodies. Cell proliferation increased with increasing cell density, as did the concentration of PRL in the medium. Antirat PRL, but not control antibody, markedly inhibited but did not eliminate cell proliferation, and this effect was diminished with increasing PRL concentration in the medium. PRL receptors were demonstrated on 40-50% of the cells by indirect immunofluorescence using a specific antirat PRL receptor monoclonal antibody. Cell surface PRL was colocalized to the same 40-50% of the cells and copatched or cocapped along with the receptors. Absence or presence of PRL receptors did not correlate with stage of the cell cycle, as judged by ethidium bromide dual labeling. Cell surface PRL was found to be on PRL-containing cells. These data have fulfilled four criteria necessary for establishment of a substance as a secreted autocrine growth factor: 1) the factor must be secreted; 2) in log growth phase, increased cell proliferation should occur at increased cell densities; 3) the cells must display a receptor for the factor; and 4) there must be a growth response to the factor. Thus we have established that PRL is an autocrine growth factor for at least 40-50% of the GH3 cell population. This, to our knowledge, is the first example of autocrine growth factor activity of a major hormone normotopically expressed.
K A Krown; Y F Wang; T W Ho; P A Kelly; A M Walker
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Endocrinology     Volume:  131     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  1992 Aug 
Date Detail:
Created Date:  1992-09-02     Completed Date:  1992-09-02     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  595-602     Citation Subset:  AIM; IM    
Division of Biomedical Sciences, University of California, Riverside 92521-0121.
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MeSH Terms
Cell Division / drug effects
Cell Membrane / metabolism
Fluorescent Antibody Technique
Pituitary Neoplasms / metabolism,  pathology*
Prolactin / immunology,  physiology*
Receptors, Prolactin / metabolism
Tumor Cells, Cultured
Grant Support
Reg. No./Substance:
0/Antibodies; 0/Receptors, Prolactin; 9002-62-4/Prolactin

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