Variation of protein kinase C-α expression in eyestalk removal-activated ovaries in whiteleg shrimp, Litopenaeus vannamei.

The regulation of female reproduction in crustaceans is controlled by a variety of hormones. Previous studies of hormone-initiated cellular mechanisms controlling ovarian maturation focused mainly on those initiated by inhibitory hormones. In order to facilitate research on ovarian development, it is necessary to gain a better understanding of factors that promote ovarian growth on the cellular level. Here, we used eyestalk ablation to firstly induce a state of ovarian maturation in Litopenaeus vannamei. Gonadosomatic index, hemolymph vitellogenin (Vg) concentrations, and Vg gene transcript levels in the ovaries were significantly elevated at 1 and 2 weeks after eyestalk ablation (P < 0.05). Correspondingly, immunoblot analysis revealed a remarkable decrease in anti-PKC-α immunoreactivity in both cytosol and membrane fractions of ovarian tissue homogenates: it was strongly apparent in intact animals, but decreased with time after eyestalk ablation, showing a stronger tendency to do so in the membrane fraction than in the cytosol fraction. Considered overall, the data presented strongly suggest that PKC-α isoform plays a role in the regulation of ovarian growth in L. vannamei through a negative-based regulating mechanism.