Abstract
Abstract
Previous work has shown the presence of C-type retrovirus-like particles in normal prostate epithelial cells from Sprague–Dawley rats. We now report attempts to alter retrovirus-like particle expression by castration and replacement of androgen, i.e., testosterone propionate (TP). The frequency of C-type viral-like particle expression in the ventral prostates from the following groups of animals was estimated by a semiquantitative electron microscopic assay: (a) normal rats, (b) normal rats that received TP for 3 days, (c) rats 3 or 6 days after castration, and (d) rats that received TP for 3 days, beginning 3 or 6 days after castration, to induce cellular hypertrophy or hyperplasia, respectively. Three or six days following castration, the frequency of C-type particle expression in the regressed ventral prostates was markedly reduced. Typical C-type viral-like particle morphology was retained for those few particles detected. In contrast, prostates with hypertrophic epithelium from rats treated with TP starting 3 days after castration exhibited moderate to high frequencies of expression of both immature and mature, and aberrant C-type-like particles. Prostates with hyperplastic epithelium from rats treated with TP starting 6 days after castration had a wide range expression frequencies comparable to that of the normal, intact control group. Prostates from TP-treated normal intact rats exhibited low to moderate frequencies of C-type particle expression and showed no major change in the morphological pattern of virus-like particle expression. It appears that androgens are, at the very least, permissive for the expression of the retrovirus-like particles by rat ventral prostate epithelial cells, and that major de novo DNA synthesis and cellular replication are probably not essential for the increased release of the virus-like particles observed after short-term castration and replacement of androgen.
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