Effect of Castration on the Expression of Androgen and Estrogen Receptors in Neurons of the Anterior Pelvic Ganglion in the Male Pig

ABSTRACT The objective of the current investigation was to determine the effect of neonatal castration on the expression of androgen receptor (AR), estrogen receptor alpha (ERα), and estrogen receptor beta (ERβ) in the neurons of the anterior pelvic ganglion (APG) in male pigs. Receptor expression was quantitatively assessed using real‐time polymerase chain reaction (qPCR) and immunohistochemistry. Ganglia were sampled from intact pigs at 7 days of age (the day of castration) and from both intact and castrated animals at 3 and 6 months postsurgery. qPCR analysis of the intact boars revealed a significantly elevated gene expression level (GEL) of AR at 6 months of age compared to 3 months and 7 days of age. Conversely, the GEL of ERα was comparable across all age groups in the intact animals. Gene expression analysis of ERβ in the pelvic ganglia of both intact and castrated pigs consistently indicated very low levels. In the 3‐month‐old castrated cohort, the GELs of AR and ERα were significantly elevated compared to those in age‐matched intact pigs. Conversely, the GEL of ERβ did not exhibit a significant difference between the castrated and intact groups. Immunofluorescence investigations complemented the qPCR data, revealing that numerous APG neurons across all control and experimental groups demonstrated immunoreactivity for AR, ERα, and ERβ, confirming the translation and presence of all three receptor types within the neuronal somata. These data collectively suggest that, in the male pig, pelvic neurons constitute a component of autonomic circuits that are highly dependent on sex steroids and are implicated in the regulation of urogenital function. Furthermore, the sensitization of these neurons to sex hormones, likely involving not only androgens but also estrogens (primarily mediated via ERα), appears to be a dynamic, maturational process that occurs during the prepubertal period.