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

Abstract

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. IntroductionThe existence and role of steroids as important endogenous factors that regulate reproductive events are well understood for many female asteroids, e.g. Pisaster ochraceus (Botticelli et al., 1961), Asterias amurensis (Ikegamiet al., 197 l), Astropecten irregularis pentacanthus (Colombo and Belvedere 1976), Asterias rubens (Dieleman and Schoenmakers 1979, Schoenmakers 1981 and Scelerasterias mollis (Xu 1987(Xu ,1989a Xu and Barker 1990a, b, c). Much less information is available on steroids in male asteroids. Voogt and Dieleman (1984) first reported that estrone and progesterone are present in the testes and the pyloric caeca of Asterias rubens and that these steroids fluctuated seasonally during the annual reproductive cycle. Nevertheless, the origin of estrogens and actual function of steroids in male starfish are still poorly understood. Furthermore, Voogt and Dieleman (1984) stated that there were significant differences in steroid levels between sexes in the pyloric

Steroids in aquatic invertebrates

“…The results suggest a stimulation of vitellogenesis by estrone, which however should not have an endogenous origin, according to metabolic studies. Similar data have been obtained in other species-Sclerasterias mollis (Xu and Barker 1990;Xu 1991) and Asterias vulgaris (Hines et al 1992a), and the authors suggest a role of sex steroids as endogenous modulators of reproduction. The possible function of vertebrate steroids was investigated by in vivo treatments with different steroids injected or added to the food (Watts and Lawrence 1987;Wasson et al 2000b).…”

Evidence of anticipatory immune and hormonal responses to predation risk in an echinoderm

“…For instance, cortisol is a steroid often referred to as the ‘stress hormone’ that is well known in aquatic vertebrates such as fishes 33 . It is also detected in non-chordate groups, including echinoderms 34 , and a spike in cortisol was recently determined to be an expression of stress in bivalves 35 and holothuroids 36 , 37 .…”