Detection of Müllerian inhibiting substance in biological samples by a solid phase sandwich radioimmunoassay

Müllerian inhibiting substance (MIS) is a 140,000-dalton glycoprotein responsible for regression of Müllerian ducts in a male embryo. It has recently been demonstrated that MIS inhibits the growth of tumors in vivo and in vitro. In this study, we have constructed a sensitive, solid phase sandwich RIA using monoclonal antibodies raised to bovine MIS. The amount of MIS detected was based on the protein concentration of Green 3, the most purified fraction of MIS available. The assay could detect 20 ng Green 3 or 0.14 pmol in physiological samples. There was no evidence of cross-reactivity of the antibodies raised to bovine MIS with chicken, rat, mouse, or human MIS.