EXPRESSION OF PROSTATIC TRH-LIKE PEPTIDES DIFFERS BETWEEN SPECIES ANDBETWEEN MALIGNANT AND NONMALIGNANT TISSUES

Thyrotropin-releasing hormone-immunoreactive peptides (iTRH) were anal yzed in normal rat and rabbit prostates and in human benign prostatic hyperplasia (BPH) and prostate cancer. Peptides were extracted from ti ssues, fractionated by anion and cation exchange chromatography, and a nalyzed by TRH radioimmunoassay. pGlu-Glu-Pro-NH2 predominated in rabb it, but accounted for only 10-15% of iTRH in rat and human BPH. Unchar ged peptides predominated in rat and human prostate. Authentic TRH (pG lu-His-Pro-NH2) is not present in rabbit prostate, but may account for up to 25% of iTRH in rat and human prostate. iTRH was virtually absen t in prostate cancer. These results demonstrate considerable heterogen eity in the expression of TRH-like peptides in the prostates of variou s animal species, and suggest decreased expression of these peptides i n prostate cancer. (C) 1993 Wiley-Liss, Inc.