Characterization of antisera raised against hypocalcin (teleocalcin) purified from corpuscles of Stannius of rainbow trout, Salmo gairdneri.

Highly specific antisera were raised against hypocalcin, a 54-kDa glycoprotein purified from the corpuscles of Stannius (CS) of rainbow trout, Salmo gairdneri. The specificity of the antisera was determined by using Ouchterlony's double immunodiffusion test, radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), and immunocytochemistry. In the double immunodiffusion test, a single precipitin line was formed between the antisera and hypocalcin. Both RIA and ELISA studies showed that serial dilutions of hypocalcin, teleocalcin, and CS extracts produced dose-response curves, whereas rat FSH, chicken LH, bovine TSH, salmon calcitonin, bovine parathyroid hormone, and human angiotensins I and II failed to cross-react with the antiserum. Immunoreactive hypocalcin was demonstrated in the plasma of a teleost (flounder), but not of an elasmobranch (dogfish). In the immunocytochemistry, most of the gland cells showed strong immunoreaction with the antisera, whereas some cells displayed no immunoreactivity.