Distribution of vasoactive intestinal peptide and calcitonin gene-related peptide immunoreactive nerve fibers and binding sites in the hamster seminal vesicle during post-natal development

The distribution of vasoactive intestinal peptide (VIP)- and calcitonin gen e-related peptide (CGRP)-immunoreactive nerves and I-125-labeled VIP- and C GRP-binding sites was studied in the hamster seminal vesicle of 12-, 30- an d 60-day-old animals. In addition, the general innervation of the seminal v esicle was examined using the general neuronal marker synaptophysin. Our results show that the densities of the overall (synaptophysin immunorea ctive) and CGRP-immunoreactive innervation is constant during the post-nata l development of the gland. However, a significant decrease in VIP-containi ng nerves is observed at the end of puberty. The autoradiographic study rev ealed that in 12-day-old animals, the epithelium presents VIP binding sites . However, in 30-day-old animals, VIP binding sites are observed in the epi thelium of only a few clumps of acini. In 60-day-old animals, the gland is composed of acini with dilated lumina where VIP binding sites are not detec ted. In all groups studied the epithelium does not exhibit CGRP binding sit es. The seminal vesicle muscle layer displays specific binding sites for bo th VIP and CGRP at all post-natal developmental times, but the density of V IP binding sites is higher in 12- than in 30- and 60-day-old animals. Our results, showing the presence of specific VIP and CGRP binding sites du ring the development of the hamster seminal vesicle, suggest that these neu ropeptides may be involved in the growth and differentiation of the gland.