The free form of insulin-like growth factor I increases in circulation during normal human pregnancy

Tomonobu Hasegawa, Y. Hasegawa, M. Takada, Y. Tsuchiya

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The main circulating insulin-like growth factor-binding protein (IGFBP) in human, IGFBP-3, markedly decreases during pregnancy, as determined by Western ligand blotting, and its decrease is due to an endogenous pregnancy-related serum IGFBP-3 proteolytic activity. Proteolysis of IGFBP-3 may result in the free form of IGF-I (fIGF-1) being liberated from or weakly bound to IGFBP-3 fragments. The purpose of this study was to determine the plasma concentration of fIGF-I and the mechanism of fIGF-I regulation during normal human pregnancy. We studied 19 normal pregnant women at 6-8 weeks gestation, 24 normal pregnant women at 28-30 weeks gestation, and 25 nonpregnant women. We measured plasma fIGF-I using a recently established immunoradiometric assay. We also measured plasma total IGF-I (free plus complexed forms of IGF- I) using immunoradiometric assay, and IGFBP-3 proteolytic activity using a IGFBP-3 protease assay. fIGF-1 levels at 6-8 weeks gestation (4.11 ± 0.23 ng/mL) and at 28-30 weeks gestation (3.67 ± 0.21 ng/mL) were significantly higher than that in nonpregnant women (2.48 ± 0.12 ng/mL; P <0.001 in both). Total IGF-I levels at 6-8 weeks gestation (168.0 ± 9.1 ng/mL) and at 28-30 weeks gestation (241.5 ± 19.0 ng/mL) were significantly lower than that in nonpregnant women (283.9 ± 12.3 ng/mL; P <0.001 at 6-8 weeks gestation and P <0.05 at 28-30 weeks gestation). All pregnant serum studied had IGFBP-3 proteolytic activity. These data indicate that during normal human pregnancy, circulatory fIGF-1 increases, probably due to IGFBP-3 proteolytic activity.

Original languageEnglish
Pages (from-to)3284-3286
Number of pages3
JournalJournal of Clinical Endocrinology and Metabolism
Volume80
Issue number11
Publication statusPublished - 1995
Externally publishedYes

Fingerprint

Insulin-Like Growth Factor Binding Protein 3
Insulin-Like Growth Factor I
Pregnancy
Assays
Plasmas
Proteolysis
Immunoradiometric Assay
Insulin-Like Growth Factor Binding Proteins
Pregnant Women
Ligands
Serum
Western Blotting

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

Cite this

The free form of insulin-like growth factor I increases in circulation during normal human pregnancy. / Hasegawa, Tomonobu; Hasegawa, Y.; Takada, M.; Tsuchiya, Y.

In: Journal of Clinical Endocrinology and Metabolism, Vol. 80, No. 11, 1995, p. 3284-3286.

Research output: Contribution to journalArticle

@article{8f46b44cef0f4108ac3615be2215c8b9,
title = "The free form of insulin-like growth factor I increases in circulation during normal human pregnancy",
abstract = "The main circulating insulin-like growth factor-binding protein (IGFBP) in human, IGFBP-3, markedly decreases during pregnancy, as determined by Western ligand blotting, and its decrease is due to an endogenous pregnancy-related serum IGFBP-3 proteolytic activity. Proteolysis of IGFBP-3 may result in the free form of IGF-I (fIGF-1) being liberated from or weakly bound to IGFBP-3 fragments. The purpose of this study was to determine the plasma concentration of fIGF-I and the mechanism of fIGF-I regulation during normal human pregnancy. We studied 19 normal pregnant women at 6-8 weeks gestation, 24 normal pregnant women at 28-30 weeks gestation, and 25 nonpregnant women. We measured plasma fIGF-I using a recently established immunoradiometric assay. We also measured plasma total IGF-I (free plus complexed forms of IGF- I) using immunoradiometric assay, and IGFBP-3 proteolytic activity using a IGFBP-3 protease assay. fIGF-1 levels at 6-8 weeks gestation (4.11 ± 0.23 ng/mL) and at 28-30 weeks gestation (3.67 ± 0.21 ng/mL) were significantly higher than that in nonpregnant women (2.48 ± 0.12 ng/mL; P <0.001 in both). Total IGF-I levels at 6-8 weeks gestation (168.0 ± 9.1 ng/mL) and at 28-30 weeks gestation (241.5 ± 19.0 ng/mL) were significantly lower than that in nonpregnant women (283.9 ± 12.3 ng/mL; P <0.001 at 6-8 weeks gestation and P <0.05 at 28-30 weeks gestation). All pregnant serum studied had IGFBP-3 proteolytic activity. These data indicate that during normal human pregnancy, circulatory fIGF-1 increases, probably due to IGFBP-3 proteolytic activity.",
author = "Tomonobu Hasegawa and Y. Hasegawa and M. Takada and Y. Tsuchiya",
year = "1995",
language = "English",
volume = "80",
pages = "3284--3286",
journal = "Journal of Clinical Endocrinology and Metabolism",
issn = "0021-972X",
publisher = "The Endocrine Society",
number = "11",

}

TY - JOUR

T1 - The free form of insulin-like growth factor I increases in circulation during normal human pregnancy

AU - Hasegawa, Tomonobu

AU - Hasegawa, Y.

AU - Takada, M.

AU - Tsuchiya, Y.

PY - 1995

Y1 - 1995

N2 - The main circulating insulin-like growth factor-binding protein (IGFBP) in human, IGFBP-3, markedly decreases during pregnancy, as determined by Western ligand blotting, and its decrease is due to an endogenous pregnancy-related serum IGFBP-3 proteolytic activity. Proteolysis of IGFBP-3 may result in the free form of IGF-I (fIGF-1) being liberated from or weakly bound to IGFBP-3 fragments. The purpose of this study was to determine the plasma concentration of fIGF-I and the mechanism of fIGF-I regulation during normal human pregnancy. We studied 19 normal pregnant women at 6-8 weeks gestation, 24 normal pregnant women at 28-30 weeks gestation, and 25 nonpregnant women. We measured plasma fIGF-I using a recently established immunoradiometric assay. We also measured plasma total IGF-I (free plus complexed forms of IGF- I) using immunoradiometric assay, and IGFBP-3 proteolytic activity using a IGFBP-3 protease assay. fIGF-1 levels at 6-8 weeks gestation (4.11 ± 0.23 ng/mL) and at 28-30 weeks gestation (3.67 ± 0.21 ng/mL) were significantly higher than that in nonpregnant women (2.48 ± 0.12 ng/mL; P <0.001 in both). Total IGF-I levels at 6-8 weeks gestation (168.0 ± 9.1 ng/mL) and at 28-30 weeks gestation (241.5 ± 19.0 ng/mL) were significantly lower than that in nonpregnant women (283.9 ± 12.3 ng/mL; P <0.001 at 6-8 weeks gestation and P <0.05 at 28-30 weeks gestation). All pregnant serum studied had IGFBP-3 proteolytic activity. These data indicate that during normal human pregnancy, circulatory fIGF-1 increases, probably due to IGFBP-3 proteolytic activity.

AB - The main circulating insulin-like growth factor-binding protein (IGFBP) in human, IGFBP-3, markedly decreases during pregnancy, as determined by Western ligand blotting, and its decrease is due to an endogenous pregnancy-related serum IGFBP-3 proteolytic activity. Proteolysis of IGFBP-3 may result in the free form of IGF-I (fIGF-1) being liberated from or weakly bound to IGFBP-3 fragments. The purpose of this study was to determine the plasma concentration of fIGF-I and the mechanism of fIGF-I regulation during normal human pregnancy. We studied 19 normal pregnant women at 6-8 weeks gestation, 24 normal pregnant women at 28-30 weeks gestation, and 25 nonpregnant women. We measured plasma fIGF-I using a recently established immunoradiometric assay. We also measured plasma total IGF-I (free plus complexed forms of IGF- I) using immunoradiometric assay, and IGFBP-3 proteolytic activity using a IGFBP-3 protease assay. fIGF-1 levels at 6-8 weeks gestation (4.11 ± 0.23 ng/mL) and at 28-30 weeks gestation (3.67 ± 0.21 ng/mL) were significantly higher than that in nonpregnant women (2.48 ± 0.12 ng/mL; P <0.001 in both). Total IGF-I levels at 6-8 weeks gestation (168.0 ± 9.1 ng/mL) and at 28-30 weeks gestation (241.5 ± 19.0 ng/mL) were significantly lower than that in nonpregnant women (283.9 ± 12.3 ng/mL; P <0.001 at 6-8 weeks gestation and P <0.05 at 28-30 weeks gestation). All pregnant serum studied had IGFBP-3 proteolytic activity. These data indicate that during normal human pregnancy, circulatory fIGF-1 increases, probably due to IGFBP-3 proteolytic activity.

UR - http://www.scopus.com/inward/record.url?scp=0028863232&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028863232&partnerID=8YFLogxK

M3 - Article

C2 - 7593439

AN - SCOPUS:0028863232

VL - 80

SP - 3284

EP - 3286

JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

SN - 0021-972X

IS - 11

ER -