Abstract: In order to study the effect of 12a-hydroxyrotenone on the fecundity of Prodenia litura (Fabricius) and its action mechanisms, the number of eggs laid per female adult of P. litura was investigated; after 12a-hhydroxyrotenone in ovary was determined with HLPC, its cytotoxicity to ovarian cells from P. litura(PL cells) was determined at 48 h after treatment by MTT assay. The effect of 12a-hydroxyrotenone on cell cycle, cell membrane potential and mitochondrial membrane potential of PL cells, and intracellular free calcium concentration in PL cells at 24 h after treatment was also tested by flow cytometry. The results showed that the number of eggs laid per female adult declined by above 80% after 12a-hydroxyrotenone was fed to P. litura larvae, and the compound could be detected from the ovarian tissues. 12a-hydroxyrotenone showed inhibitory activity to PL cells, with IC₅₀being 6.6 mg/L at 48 h after exposure. After PL cells were treated with 12a-hydroxyrotenone for 24 h, the percentage of S phase cells markedly increased in cultured PL cells (P<0.05), while the percentage of G₂-M phase cells decreased. Cell membrane potential, mitochondrial membrane potential and the intracellular free calcium concentration in PL cells were significantly higher than those of the control groups. 12a-hydroxyrotenone led to a linear decrease in the number of eggs laid per female and PL cell cycle arrest in S phase. 12a-hydroxyrotenone exhibited weak cytotoxicity to PL cells, and caused some of them to death. Thus the number of ovarian cells decreased, and the ovary development was inhibited so that ovarian cells could not develop into mature ooctyes and its fecundity obviously decreased.

Key words: Prodenia litura, 12a-hydroxyrotenone, fecundity, cytotoxicity, cell cycle, intracellular free calcium concentration, mitochondrial membrane potential