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

This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: clinchem.2005.048504v1 51/9/1746    most recent Submit an electronic Letter to the Editor about this paper Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend 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 ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Schiettecatte, J. Articles by Smitz, J. Search for Related Content PubMed PubMed Citation Articles by Schiettecatte, J. Articles by Smitz, J. Related Collections Endocrinology and Metabolism

Immunoprecipitation for Rapid Detection of Macroprolactin in the Form of Prolactin–Immunoglobulin Complexes

¹ Laboratory of Radioimmunology and² Department of Endocrinology, University Hospital, Vrije Universiteit, Brussels, Belgium;

^aaddress correspondence to this author at: Laarbeeklaan 101, B-1090 Brussels, Belgium; fax 32-2-477-50-60, e-mail Johan.Schiettecatte@az.vub.ac.be

The first 300 words of the full text of this article appear below.

The 3 major forms of serum prolactin (PRL), identifiable by gel-filtration chromatography (GFC), are monomeric PRL (23 kDa), big PRL (45–60 kDa), and big, big PRL or macroprolactin (150–170 kDa) (1). The common macroprolactin is PRL complexed with human IgG, but aggregates of PRL, some extensively glycosylated, may also occur (2)(3)(4)(5)(6).

Macroprolactin has slower serum clearance than monomeric PRL and little or no apparent in vivo bioactivity, probably because it does not cross capillary walls (7)(8). Macroprolactin causes diagnostic confusion in evaluating hyperprolactinemia (9)(10).

Polyethylene glycol (PEG) precipitation is a rapid screening method for macroprolactinemia (11)(12)(13)(14)(15)(16)(17), but PEG interference with PRL assays limits its general use. The method, moreover, shows nonspecific precipitation (up to 15%), necessitating use of a gray zone.

We recently validated a screening method based on recognition of the IgG component of macroprolactin by anti-IgG-agarose (18); this method, however, had insufficient PRL assay sensitivity for use in moderate hyperprolactinemia (PRL <1000 mIU/L). A more rapid screening method based on PRL-IgG precipitation with protein A-Sepharose was described recently (19).

We report a simple, rapid method, also based on precipitation of PRL-IgG complexes, with protein G-agarose (PGA) suspension and high IgG binding capacity (20 mg/mL of resin). The protein G polypeptide binds the Fc region of all subclasses of the human IgG molecule and also binds the IgG3 fraction (20). Results with this method were compared with those from GFC and PRL-PEG precipitation.

For GFC, we used the fast FPLC system (Pharmacia) with a Superdex 200 HR10/300 prepacked column (Amersham Pharmacia) (11). Serum (100 µL) was applied . . . [Full Text of this Article]

The following articles in journals at HighWire Press have cited this article:

				L. Kavanagh, T. J. McKenna, M. N. Fahie-Wilson, J. Gibney, and T. P. Smith Specificity and Clinical Utility of Methods for the Detection of Macroprolactin Clin. Chem., July 1, 2006; 52(7): 1366 - 1372. [Abstract] [Full Text] [PDF]