EFFECTS OF CADMIUM ON STEROL COMPOSITION IN THE ABORAL BODY-WALL OF THE SEA STAR ASTERIAS-RUBENS L

1. Sterol composition of the aboral body-wall of male specimens of Ast erias rubens starved for three weeks, was compared with that of male s ea stars which during the starvation period had been exposed to cadmiu m (100 mug/l.). 2. Sterol composition of non-exposed animals appeared to be constant as assessed over a period of four years. 3. Cadmium-exp osure strongly influenced sterol composition. The effect was related t o the reproductive cycle, effects being different in the spermatogenic and the aspermatogenic phase. 4. Effects on total C27-, C28-, DELTA7. 22-, and some individual sterols showed abrupt changes in November and March, coinciding with the start and the end of the reproductive cycl e. 5. In one experiment additional parameters were determined. Cadmium -exposure resulted in a significant increase of polar lipids in the bo dy-wall and a decrease of the sterol/phospholipid ratio. The increase of polar lipids was accompanied by a decrease of C28-sterols. Conseque nces for viscosity are discussed. 6. Cadmium-exposure also resulted in a decrease of phosphatidylserine and an increase of phosphatidylethan olamine.