ISOLATION AND CHARACTERIZATION OF CDNA CLONES FOR CASTRATION-INDUCED MESSENGER-RNAS IN THE RAT VENTRAL PROSTATE

To identify gene products involved in castration-induced involution of the rat ventral prostate, we constructed a substraction cDNA library of the ventral prostate from rats castrated for 48 h. The library was screened with subtracted cDNA probes enriched for sequences with a low copy number expressed in intact or castrated rats. As a result of dif ferential screening, 48 cDNA clones representing 10 different induced mRNAs were isolated. The time course of these mRNA inductions after ca stration was examined. Within the first 24 h after castration, the lev el of mRNAs for these cDNA clones was significantly increased and it r eached its peak by 48-72 h after castration. Although mRNAs for these cDNA clones were expressed in various tissues from intact rats, an inc rease in mRNA as a response to castration was observed only in the ven tral prostate. Partial sequence analyses of the 10 cDNA clones indicat e that three cDNA clones represent rat glutathione S-transferase Yb-1, Yb-2 and Yb-3 subunit mRNA sequences, but for other respective homolo goues could not be found in a search of the GenBank database (release 67).