[Metabolism of steroids in the central nervous system and pituitary of various mammals].

The central nervous system and pituitary of various mammals were examined by radioautography after injection of different tritiated steroid hormones. After injection of 3H estradiol into ovariectomized mice, radioautograms revealed a significant labelling in cells of the amygdala, the bed nucleus of the stria terminalis, the nucleus preopticus medialis, the nuclei arcuatus and ventro-medialis. The radioactive material was associated with the cell nuclei. Certain anterior lobe cells retained the hormone. After injection of 3H testosterone into castrated rats, the central nervous system and the anterior pituitary contained labelled cells. In the hypothalamus, the distribution pattern of androgen-neurons appears to be similar from the estrogen-neuron areas, although some differences in the number of cells and the intensity of labelling seen to exist. After injection of 3H progesterone into castrated estrogen-primed guinea-pigs, labelled neurons have been observed in the regions of nucleus arcuatus and nucleus preopticus suprachiasmaticus. However, the presence of progesterone receptors in the hypothalamus has not been still clearly demonstrated. After injection of 3H corticosterone into adrenalectomized male rats, radioactivity was found to be selectively concentrated in neurons of septum, hippocampal complex (precommissural hippocampus, cornu Ammonis, gyrus dentatus, subiculum) indusium griseum, amygdala and in certain areas of the cortex. Most of the silver grains were localized in the nuclei of labelled cells. On the other hand, after injection of 3H dexamethasone radioactivity concentration was high in the medial basal hypothalamus, in the anterior pituitary and in the pineal gland. Differences appear to exist in the topographic distribution of dexamethasone and corticosterone-concentrating cells.