Female-specific Lipoprotein Level in Hemolvmph during Egg Formation in Freshwater Shrimp

Abstract

In order to elucidate the mechanism of vitellin deposition into the ovary, the hemolymph lipoprotein was electrophoretically analyzed in a freshwater shrimp Palaemon paucidens.
Totally 16 lipoproteins were detected in the pregnant female hemolymph by polyacrylamide gradient gel electrophoresis at pH 8.25. The hemolymph level of female-specific lipoproteins (FSL) varied periodically in the course of vitellogenesis.
The duration of molting stage B was characteristically elongated by reproduction. The pregnant shrimp molted when maximum egg diameter (MED) in the ovary grew to about 600μm, neverthless molting process was depressed by reproduction. In the ovary stage of MED below 600 μm, FSL level was high in molting stages B and D. In MED above than 600 μm, it was high only in stage B. The level gradually fell prior to maturation.
The characteristic rise of FSL at the molting stage B which was elongated by reproduction refleted the competitive hormonal interaction between reproduction and molting process.