ABSTRACT
Body wall, pyloric caeca/gut and gonadal tissue minces of four asteroids, three echinoids, three ophiuroids, a holothuroid, and a crinoid were incubated with 3H-androstenedione, the primary steroid precursor in androgen synthesis. Steroid metabolites were identified by TLC, chemical derivatization and recrystallization to constant specific activity. Relative amounts of synthesized steroid metabolites were determined using a radioisotope imaging scanner. All tissues of the taxa examined metabolized androstenedione into a variety of steroids and steroid derivatives. The pyloric caeca/gut tissues demonstrated higher rates of androstenedione conversion (per unit wet weight) when compared to body wall and gonads. The primary metabolite produced in all tissues (except the ophiuroid gut) was testosterone. Secondary major metabolites included 5α-androstanedione and epiandrosterone. Minor metabolites included 5ß-androstanedione, 5α-androstane-3ß,17ß-diol, 5α-dihydrotestosterone, unknown esterified androgens (including testosterone and etiocholanolone) and steroid conjugates (presumably glucuronides or sulphates). 11ß-Hydroxytestosterone and 11-ketotestosterone, several unknown polar (organic soluble) metabolites and several relatively non-polar metabolites were observed. These metabolites were not present in all tissues or species. Qualitative and quantitative differences in androgen synthesis may be related to tissue specific functions or reproductive periodicity.
