DEVELOPMENT OF PEPTIDE-CONTAINING NERVES IN THE HUMAN FETAL PROSTATE-GLAND

Immunohistochemical methods were used to study the developing peptider gic innervation of the human fetal prostate gland in a series of speci mens ranging in gestational age from 13 to 30 wk. The overall innervat ion of each specimen was visualised using protein gene product 9.5 (PG P), a general nerve marker. The onset and development of specific neur opeptide-containing subpopulations were investigated using antisera to neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), bombesin (BOM), somato statin (SOM), leu-enkephalin (1-ENK) and met-enkephalin (m-ENK). In ad dition the occurrence and distribution of presumptive noradrenergic ne rves was studied using antisera to dopamine-beta-hydroxylase (DPH) and tyrosine hydroxylase (TH). At 13 wk numerous branching PGP-immunoreac tive (-IR) nerves were observed in the capsule of the developing prost ate gland and surrounding the preprostatic urethra but the remainder o f the gland was devoid of nerves. The majority of nerves in the capsul e contained D beta H and TH and were presumed to be noradrenergic in t ype while other nerves (in decreasing numbers) contained NPY, 1-ENK, S P and CGRP. Nerves associated with the preprostatic urethra did not co ntain any of the neuropeptides under investigation. At 17 wk the densi ty of nerves in the capsule had increased and occasional m-ENK-, VIP- and BOM-IR nerve fibres were also observed. In addition PGP, D beta H- , TH-, NPY- and 1-ENK-IR nerves occurred in association with smooth mu scle bundles which at 17 wk were present in the outer part of the glan d. Occasional PGP-IR nerves were also present at the base of the epith elium forming some of the prostatic glands. At 23 wk some of the subep ithelial nerves showed immunoreactivity for NPY, VIP or 1-ENK. At 26 w k smooth muscle bundles occurred throughout the gland and were richly innervated PGP, D beta H and TH-IR nerves while a less dense plexus wa s formed by NPY- and 1-ENK-IR nerves together with a few m-ENK-IR nerv es. Occasional smooth muscle-associated varicose nerve fibres showed i mmunoreactivity for SP, CGRP, VIP or BOM although the majority of thes e types of nerve formed perivascular plexuses. Also at 26 wk numerous varicose nerve fibres were observed in association with the prostatic acini, the majority of such nerves containing NPY with a few showing i mmunoreactivity to VIP, 1-ENK, SP or CGRP. The relative paucity of VIP -IR nerves from the subepithelial plexus of the fetal prostatic acini is in marked contrast to the adult gland. Furthermore, unlike the situ ation in adults, PGP-IR ganglion cells were not present within the sub stance of any of the fetal prostate specimens included in this study. Randomly scattered endocrine-paracrine epithelial cells immunoreactive for CGRP were present in the prostatic glands and prostatic urethra a t 13 wk gestation. Similar cells immunoreactive for BOM were first app arent in the prostatic and urethral epithelium at 20 wk. Occasional ce lls immunoreactive for SOM were first observed in the urethral epithel ium at 22 wk and in the prostatic acini at 30 wk.