A liquid-phase two-site immunoradiometric assay for human prolactin

Area of Science:

• Endocrinology
• Immunochemistry
• Assay Development

Background:

• Accurate measurement of human prolactin (hPrl) is crucial for diagnosing various endocrine disorders.
• Traditional radioimmunoassays (hPrl RIAs) often require long incubation times and exhibit limited sensitivity and operating ranges.
• Development of novel, efficient, and sensitive assays for hPrl is an ongoing area of research.

Purpose of the Study:

• To develop and characterize a novel 'two-site' immunoradiometric assay (IRMA) for human prolactin (hPrl).
• To compare the performance of the developed hPrl IRMA with a conventional hPrl radioimmunoassay (RIA).
• To optimize assay conditions for improved sensitivity, speed, and operating range.

Main Methods:

• A two-site immunoradiometric assay was developed using radio-iodinated sheep anti-hPrl immunoglobulin G (IgG) and rabbit anti-hPrl serum.
• Solid-phase reagents were omitted to minimize non-specific effects and reduce incubation time.
• Separation of bound and free labeled antibody was achieved via precipitation using sheep anti-(rabbit IgG) serum.

Main Results:

• The developed hPrl IRMA demonstrated rapid reactant equilibration and high sensitivity (2.6 mU/l, 13 pg).
• The hPrl IRMA exhibited a wide operating range (precision <10% from 8-10000 mU/l).
• Compared to the hPrl RIA (18 h incubation, sensitivity 9.8 mU/l), the IRMA required only 3 h incubation with superior performance.

Conclusions:

• The novel two-site immunoradiometric assay provides a rapid, sensitive, and wide-ranging method for human prolactin quantification.
• Eliminating solid-phase reagents and optimizing antibody addition order enhances assay efficiency.
• This hPrl IRMA represents a significant improvement over conventional hPrl RIAs for clinical and research applications.