Vertebrate steroids and the control of female reproduction in two decapod crustaceans, Emerita asiatica and Macrobrachium rosenbergii

• Published in: Current science (Bangalore) Vol. 90; no. 1; pp. 119 - 123
• Main Authors: Gunamalai, V., Kirubagaran, R., Subramoniam, T.
• Format: Journal Article
• Language: English
• Published: Current Science Association 10-01-2006
• Subjects: Crabs; Crustaceans; Ecdysteroids; Emerita asiatica; Freshwater; Hemolymph; Hepatopancreas; Macrobrachium rosenbergii; Molting; Ovaries; RESEARCH COMMUNICATIONS; Steroids; Vertebrates; Vitellogenesis; ISW, India
• ISSN: 0011-3891

Vertebrate steroids, estradiol-17β (E₂) and progesterone (P), have been estimated in the hemolymph, ovary and hepatopancreas of mole crab Emerita asiatica and freshwater prawn Macrobrachium rosenbergii during the reproductive and molt cycle stages by radioimmunoassay. The maximum level of E₂ in hemolymph, ovary and hepatopancreas was detected only during the intermolt stage, whereas the level gradually decreased during premolt and postmolt stages in E. asiatica. The E₂ level in the hemolymph was high in crabs with mature ovaries, while those with quiescent ovaries were low or undetectable. The trend in P level in all tissues during different molt and reproductive stages was remarkably similar to that of E₂. However, in M. rosenbergii, with two types of molt cycles, viz. reproductive and common (non-reproductive) molt, E₂ and P levels in hemolymph, ovary and hepatopancreas showed wide variation between them. During the reproductive molt cycle, the level of E₂ and P in all tissues peaked during intermolt, but declined drastically at premolt and postmolt stages. On the contrary, the level of E₂ in hemolymph was not detectable in any molt stage during the non-reproductive molt with the ovary containing undeveloped oocytes. However, the inactive ovary and hepatopancreas showed basal level of E₂ during non-reproductive molt cycle, whereas P was totally undetectable in the above tissues. Cumulatively, these studies suggest that the ovary may synthesize E₂ and release them into the hemolymph from where it may reach the hepatopancreas to stimulate vitellogenin synthesis in the two decapods. P may have a role in the post-vitellogenic meiotic maturation of the oocytes, as in vertebrates.