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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
journal contribution
posted on 1991-12-01, 00:00 authored by S E Gargosky, P C Owens, P E Walton, Julie OwensJulie Owens, J S Robinson, J C Wallace, F J BallardThe 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)
History
Journal
Journal of endocrinologyVolume
131Issue
3Pagination
491 - 497Publisher
BioscientificaLocation
Bradley Stok, Eng.Publisher DOI
ISSN
0022-0795Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
1991, Journal of Endocrinology LtdUsage metrics
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No categories selectedKeywords
Blotting, WesternCarrier ProteinsChemical FractionationChromatographyFemaleHumansInsulin-Like Growth Factor Binding ProteinsInsulin-Like Growth Factor IInsulin-Like Growth Factor IIMolecular WeightPregnancyScience & TechnologyLife Sciences & BiomedicineEndocrinology & MetabolismFACTOR-BINDING-PROTEINSERUM HALF-LIFEIGF-IHORMONEPLASMASOMATOMEDINSPEPTIDEACIDPIGSRAT
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