In:
Journal of Neuroendocrinology, Wiley, Vol. 9, No. 6 ( 1997-06), p. 423-430
Abstract:
Basic fibroblast growth factor (FGF‐2) is not only a potent mitogen for various cells but also a multifunctional factor with angiogenic and chemotactic activity, and the capacity to induce the synthesis of various proteinases and to modulate endocrine function. To clarify the role played by FGF‐2 in the progression of pituitary tumor, we fused rat FGF‐2 cDNA to the promoter SR α , consisting of the early promoter of SV40 and HTLV(I)‐LTR, and we cotransfected GH 3 cells with pSV2‐neo by an electroporation method. After selection by G418, we obtained 7 neomycin‐resistant clones. Southern blot analysis of genomic DNA revealed the presence of transfected rat FGF‐2 cDNA in 4 of the 7 clones. To measure FGF‐2 molecules, we established a new immuno‐fluorometric assay system, using 3 monoclonal antibodies against different portions of human FGF‐2. This assay had a minimum sensitivity of 10 pg/ml and cross‐reacted neither with acidic fibroblast growth factor (FGF‐1) nor insulin‐like growth factor 1 (IGF‐1), even at a concentration of 100 ng/ml. Although FGF‐2 was undetectable in the culture medium of any of the clones, the cell homogenate contained a significant amount of FGF‐2 (7.2 ng/mg protein) in 1 of the 4 FGF‐2‐transfected clones (GH 3 FGF(+)), whereas FGF‐2 was not detected ( 〈 5.2 pg/mg protein) in the cell homogenates of either the parent GH 3 cells or the control cells transfected with pSV2‐neo alone (GH 3 FGF(−)). GH 3 FGF(+) grew as adherent cells and formed epithelial sheets with a growth rate similar to that of control cells. The amount of prolactin(PRL) released by TRH was greater in GH 3 FGF(+) than that in GH 3 or GH 3 FGF(−). On the other hand, the sensitivity to SRIF was increased in GH 3 FGF(+) compared with that in other clones. The findings of these in vitro studies indicate that FGF‐2, if it is expressed in pituitary tumor cells, plays little if any role in cell growth but may modulate certain cell functions such as responsiveness to hormones.
Type of Medium:
Online Resource
ISSN:
0953-8194
,
1365-2826
DOI:
10.1046/j.1365-2826.1997.00591.x
Language:
English
Publisher:
Wiley
Publication Date:
1997
detail.hit.zdb_id:
2007386-0
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