RELATIONSHIP OF NEUROENDOCRINE CELLS OF PROSTATE AND SEROTONIN TO BENIGN PROSTATIC HYPERPLASIA

Neuroendocrine (NE) cells containing neurosecretory granules, rich in various peptide hormones and biogenic amines such as serotonin (5-HT), are components of the human prostate epithelium. The NE cells probabl y subserve a paracrine or local regulatory role in both prostatic grow th and differentiation as well as the exocrine secretory process. Neur oendocrine cells may be involved in the etiology of benign prostatic h yperplasia (BPH). In this study the number of NE cells in areas of BPH was compared with normal tissue using 5-HT immunocytochemistry. In ad dition, using high-performance liquid chromatography with electrochemi cal detection (HPLC-ECD), tissue levels of 5-HT and its metabolite 5-h ydroxy-indoleacetic acid (5-HIAA) were analyzed in prostatic tissue ex tracts including 25 cases of BPH and 16 cases of normal tissue verifie d by adjacent histologic sections. Compared with normal prostate our r esults demonstrated a marked decrease in 5-HT immunoreactive NE cells in the vast majority of larger hyperplastic nodules of BPH. These find ings were corroborated by quantitative analysis where a significant re duction in the tissue 5-HT levels in BPH (0.539 +/- 0.09 SE) compared with normal (1.75 +/- 0.22 SE) (p < 0.05) was found. When smaller nodu les of BPH were studied, abundant NE cells, equal or increased in numb er compared with those in adjacent normal prostatic tissue, were seen. The small apparently developing BPH nodules and ductal-like structure s contained NE cells which may be growth foci near the periphery of so me hyperplastic nodules. These findings particularly in small hyperpla stic nodules suggest that NE cells and their products are involved in controlling cell proliferation through a paracrine hormonal mechanism and may be involved in the pathogenesis of BPH. Serotonin (5-HT) and N E peptides may represent that elusive local ''missing link'' often all uded to in various theories relating to the development of early nodul ar hyperplasia in BPH.