Androgen receptor immunoreactivity in rat occipital cortex after callosotomy

Abstract

Gonadal steroidogenesis can be influenced by direct neural links between the central nervous system and the gonads. It is known that androgen receptor (AR) is expressed in many areas of the rat brain involved in neuroendocrine control of reproduction, such as the cerebral cortex. It has been recently shown that the occipital cortex exerts an inhibitory effect on testicular stereoidogenesis by a pituitary-independent neural mechanism. Moreover, the complete transection of the corpus callosum leads to an increase in testosterone (T) secretion of hemigonadectomized rats. The present study was undertaken to analyze the possible corticocortical influences regulating male reproductive activities. Adult male Wistar rats were divided into 4 groups: 1) intact animals as control; 2) rats undergoing sham callosotomy; 3) posterior callosotomy; 4) gonadectomy and posterior callosotomy. Western blot analysis showed no remarkable variations in cortical AR expression in any of the groups except in group I where a significant decrease in AR levels was found. Similarly, both immunocytochemical study and cell count estimation showed a lower AR immunoreactivity in occipital cortex of callosotomized rats than in other groups. In addition, there was no difference in serum T and LH concentration between sham-callosotomized and callosotomized rats.In conclusion, our results show that posterior callosotomy led to a reduction in AR in the right occipital cortex suggesting a putative inhibiting effect of the contralateral cortical area.

Testosterone Effects on the Brain in Transgender Men

“…Given that both the occipital and insular cortices express androgen receptors (Clark et al 1988;Simerly et al 1990;Kolb and Stewart 1991;Goldstein et al 2001;Lepore et al 2008) it is important to discuss also a possibility that the presently detected increases in Cth could simply reflect trophic testosterone receptor-mediated effects (see also Lentini et al 2013). This seems, however, unlikely, albeit not exclusive, as such effects would be expected also in certain subcortical volumes expressing androgen receptors, for example, the amygdala and thalamus (Filipek et al 1994;Giedd et al 1997;Goldstein et al 2001), which was not found.…”