Effects of estramustine and megestrol on ultrastructure of rat ventral prostate

The effects of estramustine phosphate on the ultrastructure of the rat ventral prostate closely resemble postcastration events, i.e., a decrease in cell size and secretory activities. The fibromuscular stroma, especially collagen fibers, appear to lose their adherence to adjoining muscle cells and fibroblasts. An infiltration of lymphocytes was noted in dilated regions of the fibromuscular stroma. There was an increase in cellular activity in the ventral prostate of rats treated with megestrol acetate with varying degrees of cellular atrophy and cytoplasmic disorganization. Squamous metaplasia was evident in one experimental group of MA-treated animals. Particles resembling mature C-type viruses were observed in several prostates from control and experimental animals.