On ecdysone-binding proteins and ecdysone-like material in nematodes.

Homogenates of Panagrellus redivivus and extracts of P. redivivus, Aphelenchus avenae and Haemonchus contortus were examined for ecdysone-binding proteins and ecdysone-like material, respectively. Sucrose density-gradient centrifugation, polyacrylamide gel electrophoresis and charcoal-dextran-binding assay failed to detect ecdysone-binding protein(s) in homogenates of P. redivivus. Ecdysone-like material was detected in extracts of the three nematodes by radioimmunoassay (RIA). The titres detected in A. avenae and P. redivivus were correlated with their population profiles. The extraction efficiency for endogenous ecdysone-like material was estimated to be 92%. The RIA did not cross-react with cholesterol at the concentrations added.