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

OBJECTIVES: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSION: 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.

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