Annual changes in the steroid levels in the testis and the pyloric caeca of Sclerasterias mollis (Hutton) (Echinodermata: Asteroidea) during the reproductive cycle

Summary

The levels of estrogens and progesterone in the gonads and pyloric caeca of male Sclerasterias mollis were determined during the annual gametogenic cycle from June 1986 to June, 1987. In the testes, the levels of progesterone and estrone were inversely related at the beginning of a new reproductive cycle whereas at the beginning of formation of spermatogenic columns they were directly related. In the pyloric caeca of S. mollis, the annual pattern of changes in steroid levels did not differ between males and females, suggesting that changes in the steroid levels are related not only to reproductive processes, but also to other factors. Differences in reproductive strategy between S. mollis and the other asteroid may result from differences in the annual patterns of changes in steroid levels.