A morphometric analysis of microtubules in relation to the inhibition of lysosome movement caused by colchicine.

Colchicine was administered intraperitoneally to rats in doses which are known to inhibit the basal migration of lysosomes in uterine epithelial cells. The fractional volume of microtubules in the cells was then measured by morphometry. Colchicine at 0.10 mg/kg reduced the microtubule content of the cells from 0.22% down to 0.15%, and 1.0 mg/kg reduced microtubule content to 0.03%. Microtubules were essentially absent from the cells after colchicine doses of 3.0 and 10.0 mg/kg. The microtubule content of uterine epithelial cells thus decreased in the colchicine dose range from about 0.10 to 1.0 mg/kg, the same dose range in which an inhibition of lysosome migration has been observed. These results support the suggestion that microtubules are necessary for the basal migration of lysosomes in uterine epithelial cells. In addition, colchicine at 1.0 mg/kg caused a redistribution of the Golgi complex and a class of electron-transparent, 130 to 450 nm vesicles. These organelles were restricted to the apical halves of the cells in untreated rats, but they were dispersed throughout the cells after drug treatment. The change in the position of the organelles may be caused by a loss of cytoskeletal function of the microtubules.