Vinblastine-induced disruption of microtubules in cockroach hemocytes

Intrahemocoelic injections of vinblastine (10(-3), 10(-4)M) resulted in the disappearance of microtubule marginal bundles in the hemocytes of Periplaneta americana L. concomitant with a change in lenticular cell shape as determined by electron microscopy. In contrast to control cells, which in section were elliptical in shape with smooth edges, treated cells displayed large vacuoles apparently resulting from folds in the cytoplasm and an irregular shape. Vinblastine concentrations lethal to insects (25micro1/insect, 10(-3)M) resulted in marginal bundle loss, and the formation of cytoplasmic linear material with associated ribosomes, although microtubule crystals were not found.