RECEPTOR BINDING PROPERTIES OF125I-hFSH PREPARED BY ENZYMATIC IODINATION

Abstract

Radioiodinated human follicle stimulating hormone (hFSH) has been prepared for receptor binding studies by lactoperoxidase catalysed iodination followed by purification on Sepharose-Concanavalin A. The ¹²⁵I-hFSH tracer prepared by this method was relatively homogeneous on gel filtration and showed specific binding of 12% to excess of rat testis homogenate. Further purification of ¹²⁵I-hFSH was performed by elution from particulate testis receptors at pH 5, with increase of specific binding to 28% during subsequent incubation with testis homogenate.