Evaluation of serum insulin-like growth factor binding proteins (IGFBP) in Angus cattle divergently selected for serum IGF-I concentration

Insulin-like growth factor binding protein-3 (IGFBP-3) is the major carrier of insulin-like growth factor I (IGF-1) in serum, and its production is growth hormone (GH) dependent. It is unclear whether in humans IGFBP-3 production is directly regulated by GH or mediated via IGF-I. We addressed this question in six patients with Laron-type dwarfism, a syndrome characterized by the absence of GH receptor activity (LTD), who were chronically treated with recombinant IGF-I. Analysis of the electrophoretic profiles of serum IGFBPs in these patients by Western ligand blotting revealed an extremely low IGFBP-3 level. A striking progressive increase in serum IGFBP-3 was observed with continuous treatment, despite the absence of GH action. In LTD children, serum IGFBP-3 increased up to 19-fold after six months of therapy and equalled levels observed in controls, whereas in adult LTD patients the increase was smaller. A rise in serum levels of 34, 30 and 24 kDa BPs (presumably IGFBP-2, -1 and -4, respectively was also noted with chronic IGF-I therapy. This proof of GH-independent induction of IGFBP-3 by IGF-1 may be a major advantage in the therapeutic use of biosynthetic IGF-I in several types of short stature children.

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Effects of Thyroid Hormone on Serum Insulin-Like Growth Factor Binding Proteins(IGFBPs) and IGFBP-2 mRNA Expression in Chickens.

Japanese poultry science ◽

10.2141/jpsa.36.155 ◽

1999 ◽

Vol 36 (3) ◽

pp. 155-166 ◽

Cited By ~ 1

Author(s):

Akira TSUKADA ◽

Takeshi OHKUBO ◽

Minoru TANAKA ◽

Kunio NAKASHIMA ◽

Masaaki WAKITA ◽

...

Keyword(s):

Growth Factor ◽

Thyroid Hormone ◽

Mrna Expression ◽

Binding Proteins ◽

Serum Insulin ◽

Insulin Like Growth Factor ◽

Factor Binding

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INSULIN-LIKE GROWTH FACTOR BINDING PROTEINS FROM PRIMARY CULTURES OF RAT OVARIAN THECA-INTERSTITIAL (ROTI) CELLS: REGULATION BY LH AND IGF-I

Pediatric Research ◽

10.1203/00006450-199305001-00293 ◽

1993 ◽

Vol 33 ◽

pp. S52-S52

Author(s):

J F Cara ◽

J Fan

Keyword(s):

Growth Factor ◽

Binding Proteins ◽

Primary Cultures ◽

Insulin Like Growth Factor ◽

Factor Binding ◽

Igf I

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Comparison of the effectiveness of various procedures for reducing or eliminating insulin-like growth factor-binding protein interference with insulin-like growth factor-I radioimmunoassays on porcine sera

Journal of Endocrinology ◽

10.1677/joe.0.1400229 ◽

1994 ◽

Vol 140 (2) ◽

pp. 229-237 ◽

Cited By ~ 22

Author(s):

R S Frey ◽

M R Hathaway ◽

W R Dayton

Keyword(s):

Molecular Weight ◽

Growth Factor ◽

Binding Proteins ◽

Insulin Like Growth Factor ◽

Factor Binding ◽

Factor I ◽

Igf I ◽

Growth Factor I ◽

Igfbp 3 ◽

Glycyl Glycine

Abstract We have examined the efficacy of various methods for reducing the interference of insulin-like growth factor-binding proteins (IGFBPs) with insulin-like growth factor-I (IGF-I) radioimmunoassays (RIAs) run on porcine sera. Acid–ethanol (AE) extraction, AE extraction followed by cryoprecipitation, glycyl–glycine (GG) extraction, GG extraction followed by Sephadex G-50 chromatography in 1 mol acetic acid/l (GG/G-50), and Sep-Pak chromatography were analysed. To provide a range of IGF-I and IGFBP levels, sera obtained from control, hypophysectomized, diabetic and somatotrophin-treated pigs were used. Recoveries of IGF-I added to sera prior to treatments other than Sep-Pak chromatography ranged from 85 to 105% and were not significantly different. In contrast, Sep-Pak chromatography gave extremely variable recoveries. 125I-Labelled IGF-I ligand blotting showed that GG extraction followed by acid G-50 chromatography was by far the most effective method of removing or inactivating IGFBPs in porcine sera. Consequently, this procedure was used as a standard against which to compare other extraction procedures. GG extraction alone removed or inactivated low molecular weight binding proteins but appeared to have little effect on IGFBP-3. AE extraction reduced the level of IGFBP-3 but had little effect on lower molecular weight binding proteins. Even though none of the tested procedures completely removed or inactivated the binding proteins, all samples yielded IGF-I displacement curves that were parallel to that obtained for IGF-I standard. Despite yielding parallel displacement curves, sera extracted by various methods gave dramatically different apparent IGF-I levels when subjected to IGF-I RIA. IGF-I RIA of GG extracted sera yielded IGF-I values that were closest to those obtained for identical serum samples subjected to glycyl-glycine extraction followed by G-50 chromatography. For sera from control, hypophysectomized, diabetic and somatotrophin-treated pigs, the relationship of the IGF-I level in GG-extracted sera to that in GG-extracted, acid G-50 chromatographed (GG/G-50) sera was √GG=1·13√GG/G-50−0·23 (r2=0·98). Consequently, GG extraction can be used to remove IGFBP interference with IGF-I RIAs of porcine sera from normal, hypophysectomized, diabetic and somatotrophin-treated animals. Journal of Endocrinology (1994) 140, 229–237

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Responses of insulin-like growth factor binding protein-1 (IGFBP-1) and the IGFBP-3 complex to administration of insulin-like growth factor-I

Acta Endocrinologica ◽

10.1530/acta.0.1280101 ◽

1993 ◽

Vol 128 (2) ◽

pp. 101-108 ◽

Cited By ~ 28

Author(s):

Robert C Baxter ◽

Naomi Hizuka ◽

Kazue Takano ◽

Sara R Holman ◽

Kumiko Asakawa

Keyword(s):

Single Dose ◽

Growth Factor ◽

Food Intake ◽

Binding Proteins ◽

Insulin Like Growth Factor ◽

Factor Binding ◽

Factor I ◽

Igf I ◽

Highly Correlated ◽

Igfbp 3

The importance of insulin-like growth factor binding proteins (IGFBPs) in modulating the bioactivity of administered IGFs is poorly understood. This study examines responses of IGFBP-1 and the IGFBP-3 complex to recombinant human IGF-I. Eight fasted subjects received a single dose of 0.1-0.125 mg/kg IGF-I sc. This caused a 10-fold rise in IGFBP-1 over 6 h. falling rapidly after food intake. Peak (6-h) IGFBP-1 values were highly correlated with peak post-prandial (8-h) glucose values (r = 0.941). IGFBP--3 showed little response, decreasing slightly over the 48-h period following IGF-I. Adaptive changes in IGFBPs were studied in fed adults injected daily for 7 days with IGF-I, 0.1 mg/kg sc. Following the first injection. IGFBP-1 had a markedly blunted response compared to that in fasted subjects. However, after the seventh IGF-I injection, a 3.5-fold greater IGFBP-1 response to the same IGF-I dose was seen. Concomitantly with the increased IGFBP-1 responsiveness, mean immunoreactive IGFBP-3 and acidlabile subunit levels decreased significantly (p< 0.005), whereas IGFBP-2 detected by immunoblotting increased. Thus IGF-I administration causes changes in IGFBPs which may be important in regulating IGF-1 bioavailability.

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Serum Insulin-Like Growth Factor Binding Protein-1 in Pregnant Women: Decreased Concentrations following an Oral Glucose Load

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456329403100107 ◽

1994 ◽

Vol 31 (1) ◽

pp. 40-45 ◽

Cited By ~ 3

Author(s):

P C O'Leary ◽

M Longley

Keyword(s):

Growth Factor ◽

Pregnant Women ◽

Binding Protein ◽

Serum Insulin ◽

Oral Glucose ◽

Insulin Like Growth Factor ◽

Oral Glucose Load ◽

Glucose Load ◽

Factor Binding ◽

Igf I

Serum concentrations of insulin-like growth factor binding protein-1 (IGFBP-1) were measured in men and in non-pregnant and pregnant women. Peak serum IGFBP-1 levels occurred mid-gestation followed by a slight decline towards term. Women with gestational diabetes had higher serum IGFBP-1 concentrations than apparently healthy women at comparable gestation. Following administration of an oral glucose load, serum IGFBP-1 concentrations were decreased within 2 h in men and in pregnant women while IGF-I levels remained constant. These results suggested that IGFBP-1 regulates IGF-I activity in pregnancy in a similar manner to that in the non-pregnant state.

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