On the nutrition and metabolism of zooplankton XIII. Further studies of steroids inCalanus

Abstract

The presence in Calanus finmarchicus of the sex hormone oestradiol-17β has been confirmed by gas chromatography-mass spectrometry (GC-MS) using the trimethylsilyl and heptafluorobutyrate derivatives.Levels of the sex hormone testosterone have been measured by radioimmunoassay in Calanus helgolandicus collected from Plymouth Sound, and in C. finmarchicus captured off the Norwegian coast. Concentrations in C. helgolandicus varied during the year from 150 to 626 fg/animal, accounting for 2.3 to 437 x 10-7% of the lipid content and 10.8 to 64.8 x 10-6%percnt; of the total sterol fraction. The mean level in Stage V C. finmarchicus, captured during spring, was 196 fg/animal.Testosterone was identified in C. finmarchicus by GC-MS of the tert-butyldimethylsilyl derivative.