Insulin-like growth factor-I (IGF-I) and retinoic acid modulation of IGF-binding proteins (IGFBPs): IGFBP-2, -3, and -4 gene expression and protein secretion in a breast cancer cell line.

Endocrinology ◽  
1992 ◽  
Vol 131 (4) ◽  
pp. 1858-1866 ◽  
Author(s):  
M L Adamo ◽  
Z M Shao ◽  
F Lanau ◽  
J C Chen ◽  
D R Clemmons ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Retinoic Acid ◽  
Growth Factor ◽  
Breast Cancer Cell Line ◽  
Cancer Cell Line ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Igf Binding

Secretion of insulin-like growth factor-I (IGF-I) and IGF-binding proteins from bovine mammary tissue in vitro

1991 ◽  
Vol 128 (2) ◽  
pp. 219-228 ◽  
Author(s):  
P. G. Campbell ◽  
T. C. Skaar ◽  
J. R. Vega ◽  
C. R. Baumrucker
Keyword(s):  
Growth Factor ◽  
Binding Proteins ◽  
Conditioned Media ◽  
Mammary Tissue ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Igf Binding ◽  
Bovine Mammary Tissue

ABSTRACT In vitro, insulin-like growth factor-I (IGF-I) promotes both growth and development of bovine mammary tissue. In vivo, the effects of IGF-I may encompass endocrine, paracrine or autocrine mediation. We addressed the possibility of paracrine/autocrine effects of IGF-I in the mammary gland by examining the in-vitro secretion of IGF-I and IGF-binding proteins (IGFBPs) from bovine mammary tissue. Bovine mammary explants from pregnant non-lactating and lactating non-pregnant animals were found to synthesize and secrete IGF-I and IGFBPs. Mammary acini cultures, representative of mammary secretory epithelia, secreted both IGF-I and IGFBP, but synthesized only IGFBP. Concentrations of IGF-I in conditioned media from explants were 1·54 and 0·72 fmol/μg DNA for pregnant and lactating animals respectively. Concentrations of IGFBPs in conditioned media from explants were similar for both physiological states at 2529 pmol 125I-labelled IGF-I bound/pg DNA. Ligand/Western blotting procedures identified four IGFBPs of 29, 33, 37 and 44 kDa for acini cultures and five IGFBPs of 28, 31, 36, 44 and 46 kDa for explant cultures. Similar affinities for IGF-I and IGF-II were shown by IGFBP, using 125I-labelled recombinant human IGF-I as the competing ligand (median effective dose (ED50) of 0·085 pmol). When 125I-labelled bovine IGF-II was used as the ligand, only bovine IGF-II (ED50 of 0·25 pmol) inhibited binding. The addition of prolactin, insulin and cortisol, with or without GH, did not affect secretion of either IGF-I or IGFBP. This report describes the ability of normal mammary tissue to synthesize and secrete IGF-I and IGFBPs. Journal of Endocrinology (1991) 128, 219–228

The effects of recombinant human insulin-like growth factor-I (IGF-I) administration on the levels of IGF-I, IGF-II and IGF-binding proteins in adolescents with insulin-dependent diabetes mellitus

1994 ◽  
Vol 142 (2) ◽  
pp. 367-374 ◽  
Author(s):  
T D Cheetham ◽  
A Taylor ◽  
J M P Holly ◽  
K Clayton ◽  
S Cwyfan-Hughes ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Growth Factor ◽  
Insulin Dependent Diabetes Mellitus ◽  
Dependent Diabetes Mellitus ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Igf Binding ◽  
Insulin Dependent ◽  
Igfbp 3

Abstract Insulin-dependent diabetes mellitus (IDDM) during puberty is associated with a reduction in circulating concentrations of insulin-like growth factor-I (IGF-I) and low IGF bioactivity. Altered levels of the IGF-binding proteins (IGFBPs), including low IGFBP-3 and elevated IGFBP-1, have also been described. These abnormalities have been linked to poor growth and deteriorating blood glucose control. We have therefore examined the effects of recombinant human IGF-I (rhIGF-I) administration on the levels of IGF-I, IGF-II, IGFBP-1, IGFBP-3 and IGF bioactivity in a group of 9 late-pubertal adolescents with IDDM. This was a double-blind placebo controlled study with each individual admitted on two occasions when either rhIGF-I (40 μg/kg) or placebo was administered by subcutaneous injection in the thigh at 1800 h. Blood samples were then taken for the subsequent 22 h. The half-life of administered rhIGF-I (12·1–22·2 h) was similar to that previously described in normal subjects. There was a small increase in IGFBP-3 concentrations overnight following rhIGF-I administration when compared to placebo, whereas the levels of IGF-II decreased. Under strict euglycaemic conditions, the relationship between insulin and IGFBP-I did not appear to be affected by rhIGF-I administration although the levels of IGFBP-1 tended to be higher overnight. IGF bioactivity was low during the placebo study, and although within the normal adult range following administration of IGF-I, was still relatively low for adolescents in late puberty. Gel filtration chromatography revealed an increase in the fractions corresponding to the 150 kDa complex throughout the duration of the study and to a lesser extent the fractions corresponding to free IGF-I which reached a maximum of 7% of total IGF-I levels. In conclusion, the subcutaneous administration of rhIGF-I in a dose of 40 pg/kg to a group of adolescents with IDDM led to a sustained increase in IGF-I levels and a rise in IGF bioactivity despite a fall in IGF-II and a trend towards higher IGFBP-1 concentrations. Journal of Endocrinology (1994) 142, 367–374

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