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Most of the circulating insulin-like growth factors-I and -II are present in the 150 kDa complex during human pregnancy.
- Source :
-
The Journal of endocrinology [J Endocrinol] 1991 Dec; Vol. 131 (3), pp. 491-7. - Publication Year :
- 1991
-
Abstract
- The aim of this study was to assess the molecular size distribution of insulin-like growth factors (IGFs) complexed to IGF-binding proteins (IGFBPs) in serum of non-pregnant and pregnant women. Sera were fractionated on a size-exclusion column at pH 7.4 to resolve different IGF-IGFBP complexes from unbound IGFs. Each fraction was further chromatographed on a size-exclusion column under acid conditions to dissociate IGFs from binding proteins prior to measurement of the IGF content of the complexes. The IGF-containing fractions from the acid column were assayed specifically for IGF-I and IGF-II. Serum pooled from pregnant women contained more IGF-I and IGF-II than serum from non-pregnant women. In both groups most of the IGF-I and IGF-II was found in a large (150 kDa) complex in serum and the remainder was present in complexes eluting in the 40-50 kDa region at pH 7.4. Some free IGF-I was also detected. Serum fractions collected by size-exclusion chromatography at pH 7.4 were also analysed by Western-ligand blotting to characterize the IGFBPs in the two main IGFBP size classes. In serum pooled from non-pregnant women, the 150 kDa IGF-IGFBP complexes contained a 40-50 kDa IGFBP doublet following Western-ligand blot analysis. This IGFBP co-migrated with a pure IGFBP-3 standard. IGFBPs of 34, 28 and 24 kDa all contributed to the 40-50 kDa IGF-IGFBP complexes of the pH 7.4 chromatograph.(ABSTRACT TRUNCATED AT 250 WORDS)
Details
- Language :
- English
- ISSN :
- 0022-0795
- Volume :
- 131
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The Journal of endocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 1723746
- Full Text :
- https://doi.org/10.1677/joe.0.1310491