Browsing by Author "Monteiro, Pedro Ribeiro Rocha"
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- In vitro metabolism of steroid hormones by ovary and hepatopancreas of the crustacean Penaeid shrimp Marsupenaeus japonicusPublication . Summavielle, Teresa; Monteiro, Pedro Ribeiro Rocha; Reis-Henriques, Maria Armanda; Coimbra, João; Monteiro, Pedro; Summavielle, TeresaRadioimmunoassay (RIA) was applied to identify selected metabolites obtained in in vitroincubations of ovarianand hepatopancreatic tissues from female Marsupenaeus japonicusin previtellogenic and vitellogenic maturation stages. Depend-ing on the precursors used, progesterone, 17α-hydroxyprogesterone or testosterone, it was possible to observe the presence of sev-eral enzymatic activities through metabolites detected in incubations. The present study provides evidence that the ovary of theshrimpM. japonicusis capable of synthesising 17β-estradiol from progesterone, evidencing the presence of 17α-hydroxy-lase, C17-C20lyase, 17β-hydroxysteroid dehydrogenase (17β-HSD) and aromatase. Enzymatic activities of aromatase, 3β-HSD and 17α-hydroxylase were detected in hepatopancreas, but not that of C17-C20lyase. These results suggest that 17β-estradiol could be the vitellogenesis stimulating ovarian hormone (VSOH), and together with former in vivoand in vitrostudies this leads us to propose that in fact there may be a physiological role for steroid hormones in the maturation cycleof crustaceans.