Purified hormones from the crustacean eyestalk and their physiological specificity

Abstract

THE amino acid compositions of two peptide hormones, both acting on the pigmentary-effector system of crustaceans, have been reported¹. One of these, erythrophore concentrating hormone (ECH) has a major function in the rapid physiological colour changes of crustaceans, by concentrating pigment granules of the erythrophores, and is the first crustacean eyestalk hormone described². The second eyestalk hormone, discovered not long afterwards³, moves the distal (DRP) and reflecting retinal pigments of dark-adapted Palaemonetes and Palaemon into the light-adapted position, but purified hormone has so far been tested on only the DRP. A third well characterised hormone, hyperglycaemic hormone (HGH), increases glucose concentration of the blood, but such hyperglycaemic responses may vary in cross tests among crustacean species^4–6. The amino acid composition of HGH has been determined. A summary of six analyses of five different preparations of HGH from eyestalks of Cancer magister is shown in Table 1; specific analyses for tryptophan have not been made. Details of the separation and purification will be reported elsewhere.