Hemolymph levels
of vertebrate-type steroid hormones in female kuruma prawn Marsupenaeus
japonicus (Crustacea: Decapoda: Penaeidae) during natural reproductive
cycle and induced ovarian development by eyestalk ablation
T. Okumur,
K. Sakiyama-2004
Fisheries
Science, 70(3):
372-380
Abstract:
The occurrence of vertebrate-type steroid
hormones in the hemolymph and ovaries has been reported in several
crustacean species; however, their physiological roles are not sufficiently
understood. In the present study, correlations between hemolymph levels of
the vertebrate-type steroid hormones and ovarian development in female
kuruma prawn Marsupenaeus japonicus were examined. In the first
experiment, hemolymph samples were taken in November (non-reproductive
period) and June (maturing and spawning period) and the hemolymph levels of
estradiol-17β, estriol, progesterone, testosterone, and
11-ketotestosterone were found not to be significantly related to the
ovarian development (gonadosomatic index, 0.80-9.39). In the second
experiment, ovarian development was induced by bilateral eyestalk ablation
in the non-reproductive period. The hemolymph levels of estradiol-17β,
estriol, and progesterone did not significantly differ between the control
female prawn and the eyestalk-ablated female prawn, which underwent
vitellogenesis. If the examined steroid hormones were
vitellogenesis-stimulating hormones as in fish, their hemolymph levels would
be expected to show significant correlations with ovarian development.
However, the present study found no significant correlations between hormone
levels and ovarian development. This suggests that based on the available
data, the examined vertebrate-type steroid hormones do not play an important
role in ovarian development in M. japonicus.
(National Research Institute of Aquaculture, Fisheries
Research Agency, Nansei, Mie 516-0193, Japan, Tel:
81-599-66-1830. Fax: 81-599-66-1962. Email: takuji@affrc.go.jp)