Effects of the avermectin, MK-243, on ovary development and salivary gland degeneration in the ixodid tick, Amblyomma hebraeum
avermectin, vitellogenesis, 20-Hydroxyecdysone, amblyomma hebraeum, MK-243, ticks
Injection of the avermectin analogue, MK-243, into engorged female Amblyomma hebraeum Koch resulted in reduced ovary weight, oocyte length, and ovary vitellin content. There was no significant reduction in hemolymph vitellogenin concentration in MK-243 treated ticks. Although MK-243 was previously shown to markedly reduce hemolymph 20E-concentration, injection of 20E, the vitellogenic hormone in this tick, did not reverse the effects of MK-243 on ovary development. These data suggest that MK-243 may exert its inhibition of egg development more at the level of vitellogenin uptake than vitellogenin synthesis. MK-243 also reversed salivary gland degeneration slightly, probably via its inhibitory effect on 20E-synthesis.
Friesen, K. J., Suri, R., & Kaufman, W. R. (2003). Effects of the avermectin, MK-243, on ovary development and salivary gland degeneration in the ixodid tick, Amblyomma hebraeum. Pesticide Biochemistry and Physiology, 76(3), 82-90. doi:10.1016/S0048-3575(03)00070-1
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