TY - JOUR
T1 - Estradiol and triiodothyronine increase production of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) by GH4C1 rat pituitary tumor cells
AU - Gilchrist, Cindy A.
AU - Park, Jung H Y
AU - MacDonald, Richard G.
AU - Shull, James D.
N1 - Funding Information:
We are gratefult o Anania Caruso,M arjorie Hrbek, and Karen Pennington for their excellent technical assistance.M uch credit and gratitude goes to Dr. KashinathP atil for his invaluableh elp with the statistical analyses,a nd many thanks to Steve Sidner and Tracy Barnett for their help with SAS programming. This work was supportedb y National Institutes of Health grants HD-24189,C A-68529,C A-09476,a nd CA-36727;a nd,N ebraskaD epartmento f Health grant 93-09R.
PY - 1995/10/30
Y1 - 1995/10/30
N2 - The main purpose of this study was to examine the effect of 17β-estradiol (E2) on the production of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBP) by GH4C1 cells, a pituitary tumor cell line that displays many phenotypic properties of the anterior pituitary lactotroph. At a low population density (10 500 cells/cm2), E2 stimulated production of IGF-I by 4.2-fold. At this density, the antiestrogen tamoxifen (TAM) had no significant effect, whereas triiodothyronine (T3), which has been demonstrated to increase the level of IGF-I mRNA in the parental GH3 cell line, stimulated IGF-I production by 3.3-fold. Both E2 and T3 also stimulated GH4C1 cell proliferation at this population density. At a four-fold higher population density (42 000 cells/cm2), E2, TAM and T3 had little effect on IGF-I production. E2 failed to stimulate proliferation of GH4C1 cells at high density, and T3 stimulated production of IGFBP-3 by 6- and 11-fold, respectively. At high density, the abilities of E2 and T3 to stimulate IGFBP-3 production were somewhat reduced. TAM had no effect on IGFBP-3 production at either population density. These data indicate that E2 and T3 stimulate production by GH4C1 cells of IGF-I through a mechanism that is sensitive to changes in population density.
AB - The main purpose of this study was to examine the effect of 17β-estradiol (E2) on the production of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBP) by GH4C1 cells, a pituitary tumor cell line that displays many phenotypic properties of the anterior pituitary lactotroph. At a low population density (10 500 cells/cm2), E2 stimulated production of IGF-I by 4.2-fold. At this density, the antiestrogen tamoxifen (TAM) had no significant effect, whereas triiodothyronine (T3), which has been demonstrated to increase the level of IGF-I mRNA in the parental GH3 cell line, stimulated IGF-I production by 3.3-fold. Both E2 and T3 also stimulated GH4C1 cell proliferation at this population density. At a four-fold higher population density (42 000 cells/cm2), E2, TAM and T3 had little effect on IGF-I production. E2 failed to stimulate proliferation of GH4C1 cells at high density, and T3 stimulated production of IGFBP-3 by 6- and 11-fold, respectively. At high density, the abilities of E2 and T3 to stimulate IGFBP-3 production were somewhat reduced. TAM had no effect on IGFBP-3 production at either population density. These data indicate that E2 and T3 stimulate production by GH4C1 cells of IGF-I through a mechanism that is sensitive to changes in population density.
KW - Estradiol
KW - Insulin-like growth factor binding protein
KW - Insulin-like growth factor-I
KW - Triiodothyronine
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UR - http://www.scopus.com/inward/citedby.url?scp=0028864402&partnerID=8YFLogxK
U2 - 10.1016/0303-7207(95)03654-P
DO - 10.1016/0303-7207(95)03654-P
M3 - Article
C2 - 8674839
AN - SCOPUS:0028864402
SN - 0303-7207
VL - 114
SP - 147
EP - 156
JO - Molecular and Cellular Endocrinology
JF - Molecular and Cellular Endocrinology
IS - 1-2
ER -