HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mesiano, S. Articles by Thorburn, G. D. Search for Related Content PubMed PubMed Citation Articles by Mesiano, S. Articles by Thorburn, G. D.

Acid–ethanol precipitation and gel filtration at acidic pH have been widely used to extract circulating binding proteins for insulin-like growth factor (IGF-I and IGF-II) from plasma or serum samples before radioligand assay for the respective IGFs. Gel filtration on Sephadex G-50 at neutral pH of neutralized acid– ethanol extracts of fetal and adult ovine plasma which had been incubated with ¹²⁵I-labelled IGF-I or ¹²⁵I-labelled IGF-II revealed that significant amounts of the IGF-binding protein activity survived the acid– ethanol extraction procedure.

Radioimmunoassay for IGF-I in acid–ethanol extracts of plasma samples from fetal, neonatal and adult sheep yielded results which depended upon the method used for separation of the antibody-bound IGF-I tracer from the free IGF-I tracer. Acid gel filtration of ovine fetal and adult plasma was found to remove completely the IGF-binding protein activity. Radioimmunoassay for IGF-I in samples of fetal, neonatal and adult sheep plasma that had undergone acid gel chromatography yielded consistent results for both methods that were used to separate antibody-bound IGF-I tracer from the free tracer.

Radioreceptor assays for IGF-II were similarly highly perturbed by the presence of binding protein in acid–ethanol extracts of ovine fetal and adult plasma. We conclude that acid–ethanol extraction can not be used reliably for the removal of IGF-binding proteins, and that only acid gel filtration is a completely safe and valid method.

J. Endocr. (1988) 119, 453–460

This article has been cited by other articles:

				Q. Qiu, J.-Y. Jiang, M. Bell, B. K. Tsang, and A. Gruslin Activation of Endoproteolytic Processing of Insulin-Like Growth Factor-II in Fetal, Early Postnatal, and Pregnant Rats and Persistence of Circulating Levels in Postnatal Life Endocrinology, October 1, 2007; 148(10): 4803 - 4811. [Abstract] [Full Text] [PDF]

				J. Khosravi, A. Diamandi, J. Mistry, and R. G. Krishna The High Molecular Weight Insulin-Like Growth Factor-Binding Protein Complex: Epitope Mapping, Immunoassay, and Preliminary Clinical Evaluation J. Clin. Endocrinol. Metab., August 1, 1999; 84(8): 2826 - 2833. [Abstract] [Full Text]