[Obtaining iodinated luteinizing hormone while preserving its biological properties]

The author describes a method of obtaining biologically-active 125I-labeled luteinzing hormone in iodation with chloramine T. The hormone and chloramine T concentration ratio of 1:2, and the reaction time of 20 sec was used. LH-125I with the specific activity of 27--30 microCi/microgram was bound with the receptor strictly specifically.