3-O-Hydrosulphato-4-hydroxyphenethylamine (dopamine 3-O-sulphate), a metabolite involved in the sclerotization of insect cuticle

Abstract

Dopamine 3-O-sulphate (3-O-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 1μmol/g wet. wt.) of dopamine 3-O-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 14C-labelled dopamine 3-O-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-O-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.