Sex steroids and 5-en-3 beta-hydroxysteroids in specific regions of the human brain and cranial nerves.

Sex steroids and 5-en-3 beta-hydroxysteroids were determined by radioimmunoassay in specific regions of the human brain, in the anterior and posterior pituitary, in one sensory organ, the retina and in the cranial nerves. Progesterone, androstenedione, testosterone and estrone were found in all areas of the brain and in all the cranial nerves but not in all cases. There was no sex difference except in the case of androstenedione where values were higher in women in some brain areas. Estrone values were always higher than those of estradiol in both men and women. No 5 alpha-dihydrotestosterone was detected in any of the samples studied. The values for pregnenolone, dehydroepiandrosterone and their sulfates were much higher than those of the sex steroids in all areas of the brain and in all the cranial nerves. Values for pregnenolone were greater than those of its sulfate while those of dehydroepiandrosterone were in general equal to or higher than those of its sulfate. The values for pregnenolone were greater than those of dehydroepiandrosterone. There were no obvious regional differences in the concentrations of the 5-en-3 beta-hydroxysteroids either in specific areas of the brain or in the cranial nerves. But there was a definite trend for the free dehydroepiandrosterone values to be higher in women. The possible significance of these observations is discussed.