A Radioimmunoassay for Rhesus Monkey Luteinizing Hormone (RhLH)

Abstract

A double antibody radioimmunoassay for rhesus monkey (Macaca mulatta) luteinizing hormone (RhLH) has been developed. Purified RhLH with a specific activity approximately 7 times that of NIH-LH-Sl was iodinated with 131I using chloramine-T. The most useful RhLH antiserum was obtained from a guinea pig immunized with a crude RhLH preparation. The useful assay range (90–20% bound) was 0.12–2.4 ng of purified RhLH, equivalent to 0.67–13 ng NIH-LH-Sl. The LH potency estimates of a number of pituitary preparations with widely varying ratios of LH:FSH and LH:TSH were in close agreement when measured by radioimmunoassay and bioassay (indices of discrimination 0.74–1.50). Dose-response curves with plasma from monkeys in various endocrinologic states were parallel to the curves obtained with pituitary LH standards, but the dose-response curve with rhesus monkey chorionic gonadotropin (RhCG), which cross-reacted but weakly, was not. {Endocrinology86: 1012, 1970)