Production of new type of antisera to thyrotropin releasing hormone (TRH) using carbodiimide coupling and an application to immunohistochemistry.

A new type of antibody was successfully produced in rabbits with TRH-BSA as an antigen. The conjugation was based on the amide bond using a carbodiimide coupling method. With this antiserum an enzyme immunoassay (EIA) for TRH was developed, and the neutralization of anti-TRH activity with an excess amount of synthetic TRH was confirmed. Very little or no cross-reaction was observed with TRH-BDB-BSA, an immunogen for generating anti-TRH serum used in previous reports. When the new type of antibodies were used for immunohistochemistry in the mammalian hypothalamus, many neuronal somata with TRH immunoreactivity were visible in animals without colchicine treatment. In addition to the known distribution of TRH cell bodies in the hypothalamus, another cell group was demonstrated to contain TRH immunoreactivity. The anti-TRH serum produced by this method should be useful for investigating extrahypothalamic TRH systems.