Radioimmunoassays for Human Chorionic Gonadotrophin and Human Hypophysial LH Using the Double Antibody Method

Abstract

Studies were performed to determine to what extend the slope of standard curves of radioimmunoassays for HCG and pituitary LH would be affected by the standard preparation and antiserum selected and by the addition sequence of labelled and unlabelled hormones. Under equilibrium conditions, labelled and unlabelled gonadotrophins were mixed prior to addition of the antiserum. Under non-equilibrium conditions, the unlabelled hormone alone was first incubated with the antiserum. In non-equilibrium conditions the slopes were steeper with HCG than with LH as standard. The slopes of the LH standard curve were flatter with some antisera than with others. The doses of both HCG and HLH had to be raised by a factor 2.8 to 4.7 to achieve the same response under equilibrium conditions as under non-equilibrium conditions.