Great Britain 3 - 0 - Hydrosulphato 4 hydroxyphenethylamine ( Dopanine 3 - 0 - Sulphate ) , a Metabolite Involved in the Sclerotization of Insect Cuticle

Dopamine 3-0-sulphate (3-0-hydrosulphato-4-hydroxyphenethylamine) was isolated from newly ecdysed cockroaches, Periplaneta americana (L.), and its structure established by chemical and physical techniques and by synthesis. Relatively high concentrations (about 1 pmol/g wet wt.) of dopamine 3-0-sulphate exist in the newly ecdysed insect, and these concentrations decrease sharply as sclerotization of the cuticle proceeds. At least 40% of the radioactivity of "C-labelled dopamine 3-0-sulphate injected into newly ecdysed nymphs was recovered in the sclerotized cuticle 7-12 days after the injection. However, less than 1% of the radioactivity of injected dopamine 3-O-[35S]sulphate was recovered, and this value was not appreciably different from that for the incorporation of Na235SO4. Apparently, little or none of the sulphate moiety of dopamine 3-0-sulphate is incorporated directly into the cuticle as the intact sulphate ester. These observations are discussed in relation to current concepts of cuticular sclerotization in insects.