TEMPORAL RELATIONSHIPS OF STATIN AND TERMININ EXPRESSION IN VENTRAL LOBE OF RAT PROSTATE FOLLOWING CASTRATION

The purpose of this study was to determine the temporal relationships, in the rat prostate following castration, the expressions of terminin , a cytoplasmic marker for senescence, and, statin, a nuclear marker f or cell quiescence and senescence. The presence of these two proteins was determined at 0, 1, 2, 4, 8, 24 and 48 hours in the ventral lobe o f the prostate following castration. Immunofluorescence techniques for double labelling were used and assessed with confocal microscopy. At 0 hour the mean % labelling index (LI) for terminin was 0 % and 98 % f or statin. One hour following castration a complete reversal of expres sion of these two markers occurred indicating that the terminin marker is expressed at the start of programmed cell death or apoptosis. The mean % LI for terminin at 1, 2, 4, 8, 24 and 48 hours following castra tion were 54, 82, 63, 39, 44 and 41 % respectively. The mean % labelli ng index of statin remained at zero during these time intervals. It is concluded that following castration, the prostatic ventral lobe exits from the quiescent phase to reenter cell cycle traverse. This is coup led by the loss of statin and the expression of the cytoplasmic marker terminin at the start of programmed cell death prior to the appearanc e of any histologic features of apoptosis.