Right occipital cortex suppresses male rat testosterone secretion by a pituitary-independent mechanism

In addition to being regulated by the hypothalamo-hypophyseal system, testosterone (T) secretion is influenced by a number of less understood mechanisms. The aim of the present study was to examine whether defined areas of the right cerebral cortex could modulate T production.

In adult male Wistar rats right frontal or occipital decortication, anterior or posterior callosotomy and corresponding sham-operations were performed. After 7-day survival time, T secretion in vitro, serum T and LH concentrations were measured by RIA.

Right occipital decortication and posterior callosotomy resulted in an increase in T secretion in vitro when compared to the corresponding sham-operated controls. In contrast, right frontal decortication or anterior callosotomy did not interfere with steroidogenesis. Serum LH concentration was not altered by any interventions.

The right occipital but not the right frontal cortex is involved in the control of T secretion. The caudal part of the corpus callosum accommodating the fibers originating from the occipital cortex might have a similar function. The fact that LH remained unchanged in all experimental groups suggests that the right occipital cortex and the caudal part of the corpus callosum influence testicular steroidogenesis by a pituitary-independent mechanism.