The Effects of Vinblastine on Isolated Xenopus Oocytes

A recent survey of the effects of various physical and chemical parameters on yolk protein incorporation by isolated Xenopus oocytes indicates that the Vinca alkaloid vinblastine sulfate (VLB) is among the more effective inhibitors of this process. The Vinca alkaloids have received considerable attention because of their ability to disrupt the integrity of microtubules; therefore, they appear to be useful tools for examining the functions of microtubules in a variety of cells. Furthermore, they facilitate the isolation and purification of microtubular proteins for biochemical studies. These properties of VLB, combined with its marked depressant effect on protein uptake by isolated oocytes, led us to examine VLB-treated oocytes for altered cytological characteristics. This communication describes alterations induced by VLB and discusses their possible significance in terms of the relationship of microtubules to the micropinocytotic uptake of protein.