A specific binding protein for the moulting hormone ecdysterone in locust haemolymph.

Specific binding of 3H-ecdysterone to a high mol. wt protein from Locusta migratoria haemolymph was shown by gel filtration. The hormone-protein complex shows a dissociation constant Kd congruent to 3.10(-7) M, and the concentration of binding sites varies during the last larval instar.