A chemical investigation into the moulting hormones of the barnacle Balanus balanoides

Abstract

In an attempt to detect and identify the moult-inducing substances in the barnacle, Balanus balanoides, one and a half metric tonnes of barnacle material was collected and extracted. Two known arthropod moulting hormones were detected in significant amounts and estimates were made of the concentrations present in the collected barnacle material using quantitative gas liquid chromatography. The major component was identified as 20-hydroxyecdysone, at a concentr- ation of lA.g.kg . However, ecdysone was detected for the first time in a crustacean at a much lower concentration of 6 ng.kg . The level of 20-hydroxyecdysone detected in the barnacle extract was comparable with the levels found in crustaceans by other workers. The presence of other possible ecdysones in the extracts was indicated by gas liquid chromatography.
Methods of determining the amounts of ecdysones in biological materials were investigated. The methods included the determination of acid-induced fluorescence in ecdysone-type compounds, and gas liquid chromatographic methods using both flame ionization and electron capture detectors. In order to make this investigation, a model steroid with some of the structural characteristics of the ecdysones was synthesised by a nine-stage process. This substance was used to investigate the spectrofluorimetrie and, initially, the gas liquid chromatographic analysis of ecdysones. The spectrofluorimetric method was found to be unsuitable for the concentrations of ecdysones expected in the barnacle extracts. The gas liquid chromatographic method of analysis, using electron capture detection of the trimethylsilyl derivatives of ecdysones, was found to be satisfactory and could detect levels as low as 10-20 picograms of ecdysones in biological materials after minimal purification.