Final answer:
Treating mammary gland epithelial cells with enzymes that digest the extracellular matrix leads to an increase in their secretory and synthetic activities, as these cells try to compensate for the loss of the supportive matrix.
Step-by-step explanation:
When mammary gland epithelial cells are placed in culture and treated with enzymes that digest the surrounding extracellular matrix, the secretory and synthetic activities of the cells increase. This is due to the epithelial cells' role in the secretion and synthesis of various compounds, including mucous and enzymes. The extracellular matrix provides structural and biochemical support to surrounding cells. Removing this matrix may induce the epithelial cells to increase production of their secretions to attempt to compensate for the loss of support. This is particularly the case when looking at glandular epithelium, which contains many secretory cells.