Development of a sensitive enzyme-linked immunosorbent assay for cattle, sheep, rat, and mouse luteinizing hormone

This manuscript reports the development of a rapid, sensitive, and specific-enzyme linked immunosorbent assay (ELISA) suitable for measuring luteinizing hormone (LH) in cattle, sheep, rats, and mice. The LH ELISA used #15 anti-LH serum-coated 96-well plates and peroxidase-labeled bovine luteinizing hormone (bLH). Bovine LH labeled with peroxidase by the periodate method was stored at -15 degrees C for over 20 mo without appreciable loss of activity. With bLH-B5 used as the standard diluted in assay buffer, the LH ELISA had a sensitivity of 79.6 +/- 31 pg/ml, and a 50% displacement point of 359 +/- 69 pg/ml. With rat LH-RP-2 (rLH) used as the standard diluted in assay buffer, the LH ELISA had a sensitivity of 102 pg/ml and a 50% displacement point of 531 pg/ml. The LH ELISA was highly specific for LH from several mammalian species. This LH ELISA was seven times more sensitive for bLH than a radioimmunoassay (RIA) with comparable sample volumes. The LH ELISA was validated for measurement of LH in buffer, tissue culture media, and sera. Depending on the sensitivity desired, the LH ELISA can be conducted in 3 to 48 h, produces no hazardous waste, and can easily be automated. Use of this LH ELISA offers improvements in speed, convenience, economy, sensitivity, and safety over comparable RIA procedures. The LH ELISA was also conducted with other monoclonal and polyclonal antibodies to LH. The LH ELISA can be performed with other LH antisera, provided the antisera has a high affinity and specificity for LH and can be uniformly coated on 96-well plates.