[University home]

The University of Manchester Library

The Phosphorylation Pattern of Insulin-Like Growth Factor-Binding Protein-1 in Normal Plasma Is Different from That in Amniotic-Fluid and Changes During Pregnancy

Westwood, M; Gibson, J M; Davies, A J; Young, R J; White, A

Journal of Clinical Endocrinology & Metabolism. 1994;79(6):1735-1741.

Access to files

Full-text and supplementary files are not available from Manchester eScholar. Use our list of Related resources to find this item elsewhere.

Abstract

We have determined the phosphorylation pattern of circulating insulin-like growth factor-binding protein-1 (IGFBP-1) in normal subjects and assessed how this changes in pregnancy. Two RIAs employing different monoclonal antibodies (MAbs 6303 or 6305) were used to measure IGFBP-1. In normal subjects, RIA 6303 measured ii-fold higher levels than RIA 6305 (72.8 vs. 6.6 mu g/L; P < 0.008). However, in amniotic fluid (AF), the two assays gave similar results. Immunoprecipitation of plasma and AF with MAb 6303 and 6305 before nonsodium dodecyl sulfate-electrophoresis and Western ligand blotting revealed different IGFBP-1 isoforms and differential antibody recognition as the cause of this discrepancy. In AF, both MAbs precipitated nonphosphorylated and phosphorylated isoforms, whereas in plasma, only a single highly phosphorylated species, not seen in AF, was observed. This form of IGFBP-1 was precipitated by MAb 6303 only. During pregnancy, the phosphorylation state of IGFBP-1 in the maternal circulation was altered, as nonphosphorylated IGFBP-1 and three lesser phosphoforms were also observed. The appearance of these other variants resulted in a significant increase in IGFBP-1 measured by RIA 6305 (37, 51, and 83 mu g/L in first, second, and third trimesters, respectively; P < 0.0005 vs. controls). The changes in IGFBP-1 phosphorylation induced by pregnancy may influence the modulatory effects of IGFBP-1 on IGF bioavailability and, hence, fetal growth.

Bibliographic metadata

Type of resource:
Content type:
Published date:
Volume:
79
Issue:
6
Start page:
1735
End page:
1741
Total:
7
Pagination:
1735-1741
ISI Accession Number:
ISI:A1994PX77500035
Related website(s):
  • Related website <Go to ISI>://A1994PX77500035
Access state:
Active

Institutional metadata

University researcher(s):

Record metadata

Manchester eScholar ID:
uk-ac-man-scw:151224
Created by:
Gibson, Martin
Created:
15th January, 2012, 15:04:11
Last modified by:
Gibson, Martin
Last modified:
1st February, 2013, 19:47:01