Karyokinetic interference in Triturus following kinetin treatment

Adult newts, Triturks viridescens, were exposed to kinetin for periods of 4 to 21 days. Mitotic Index of the intestinal nest cells of kinetin treated newts was about 8–15 times higher than the controls and in the liver capsule cells, about 8 times higher than the controls. In the newt, the lack of an observable spindle apparatus and the condition of the chromosomes is strikingly similar to the effect of colchicine. Following a pulse injection of tritiated thymidine, it was observed that no differences existed in the number of cells incorporating tritiated thymidine in the kinetin-treated and control animals within each area. Thus it appears that in the newt, kinetin does not stimulate mitosis but interferes with the completion of karyokinesis by prolonging mitotic time.