The variations of vertebrate-type steroid hormones in the freshwater narrow-clawed crayfish Astacus leptodactylus (Eschscholtz, 1823) (Decapoda, Astacidae) during oocyte development

Abstract

In this study, the levels of 17β-oestradiol (E2) and 17α-hydroxyprogesterone in the haemolymph, ovary and hepatopancreas of the freshwater narrow-clawed crayfish, Astacus leptodactylus (Eschscholtz, 1823) were analysed in different stages of oocyte development. In recent years, the occurrence of vertebrate-type steroid hormones, E2 and 17α-hydroxyprogesterone, has been reported in a few decapods, although their precise role in female reproduction is not fully elucidated. Thirty specimens of A. leptodactylus were caught at Aras Dam (Western Azerbaijan, Iran) and maintained under experimental conditions (at 25°C with a photoperiod of 14 : 10 hours light/dark) from November to March 2010. For steroid extraction, 3 ml haemolymph was withdrawn from the pericardial cavity with a syringe, and frozen at −20°C. The pieces of ovary and hepatopancreas were homogenized with phosphate buffer (pH 7.8) and, centrifuged at 3000 rpm for 15 min at 4°C as well. It was observed that the level of E2 increased in haemolymph and ovary during vitellogenesis, and decreased in the hepatopancreas. The level of 17α-hydroxyprogesterone was enhanced in haemolymph and ovary during the maturation stage. Maximum levels of E2 and 17α-hydroxyprogesterone were present in the ovary. The results point out the possible involvement of vertebrate-type steroids in the endocrine regulation of the ovarian cycle of A. leptodactylus.