[The structural organization of the cytoskeleton of the mammary secretory cells].

A study was made of the arrangement and specialties of distribution in the mammary secretory cells of albino mice of the following cytoskeleton ultrastructures: microtubules (MT), organization centres (MTOC), microfilaments (MF) and intermediate filaments (IF). During the last period of pregnancy and at different stages of lactation, for the alveolar epithelium the presence of a single material centrioles (CN) was shown in the region of the apical surface near dense intercellular contact. During pregnancy and especially at the beginning of lactation (1-2 days) the relatively large density of the MT was observed in both the cytoplasm of the secretory cells and the region near the CN. On the most hard days of lactation (10 day) the lowering of the number of all the observed structures was held in the majority of the cells. The MT was not observed near the CN. It appeared that the elimination of the MTOC activity during the most hard time of lactation is related to the decrease in the numbers of MT, MF and IF. The pattern of cytoskeleton reorganization, associated with the development of the functional activity of the observed cells, enables us to suggest a cooperative contribution of its base components in the formation of the secretory surface and in the carrying out of exocytosis.