Differences in cultures of primary mammary cells from F344 and Lewis rats and cellular localization of α-amylase. One day after preparation, epitheloids from F344 (a) showed a faster and better attachment and a more effective growth in comparison to those from Lewis rats (b). Detection of α-amylase (Cy3; red) was performed in mammary gland cells from F344 (c) and Lewis (d) rats (P1). Nuclei were stained with DAPI (blue). Pictures show cells in xy- and xz-axis by confocal microscopy. α-Amylase was present in F344 and Lewis cells. However, in Lewis cells, α-amylase was distributed throughout the whole cell, whereas in F344 cells it was found in a more granular manner near the nuclei (xz-axis).