Occurrence of follicle-stimulating hormone-like substance in the Kuruma prawn, Marsupenaeus japonicus, during ovarian maturation

The identification of vertebrate follicle-stimulating hormone (FSH) may further elucidate the reproductive mechanisms in the prawn Marsupenaeus japonicus. By immunohistochemistry, FSH-like neurons were detected in the brain and thoracic ganglia of the female kuruma prawn. By enzyme-linked immunosorbent assay (ELISA), concentrations of an FSH-like substance were determined in the brain, thoracic ganglia and haemolymph during the maturation of the ovaries. Peak levels of an FSH-like substance culminated in the brain and thoracic ganglia during the exogenous vitellogenic stage, while the maximum level of the FSH-like substance was detected in the haemolymph. Our results indicated that the vertebrate FSH-like substances are present in M. japonicus, suggesting they may be involved in the ovarian maturation.