[Nuclear spheroids in neurons of the human hypothalamus]

Morphological structure, distribution and frequency of the so-called "nuclear spheroids" have been studied in the human hypothalamus. The following results were obtained: 1. By light microscopy, the nuclear spheroids turned out to be small or large spheroid bodies inside the nucleus. They are almost homogeneous, rarely granular, vacuolar or reticular and occasionally they are multiple. They are best stained with the cresyl-violet technique. They do not exhibit any histochemical pecularities. Aside from typical nuclear spheroids, irregularly shaped nuclei were frequently seen, associated with increased nuclear folds, transitional stages between nuclear folds and nuclear spheroids were also present. Certain microscopic features suggest invagination and displacement of nuclear membrane and cytoplasm into the karyoplasma. 2. By electron microscopy, the nuclear spheroids consist of nuclear membranes and cytoplasmic constituents. They, therefore, actually represent cytoplasm protruding into the cell nucleus. 3. The nuclear spheroids occur almost regularly and most frequently in the ventromedial field of the tuber cinereum, foremost in the infundibular (= arcuate) nucleus. They numerically increase during life. They are rarely found in the ventromedial nucleus but do occur in most of the adults. In the paraventricular nucleus, the supraoptic nucleus, the lateral nuclei tuberis, and in lateral hypothalamic nucleus, they are found by far less often. They scarcely develop in the preoptic area, in the dorsal field, in the tubero-mamillar complex, in the parafornical nuclear groups, in the premamillary nucleus and in the mamillary nuclei. 4. Within the infundibular (= arcuate) nucleus, the nuclear spheroids are particularly numerous in the basal and basolateral regions, whose neurons, under certain functional conditions--such as the Sheedan syndrome, in the menopause and in association with pituitary neoplasms-, appear hypertrophic. Within the hypertrophic neurons of this region, which we designate the subventricular part of the infundibular nucleus, nuclear spheroids are definitely more frequent, and they are of the large type. 5. A separation of the subventricular part based on the distributional pattern of the nuclear spheroids indicates a pathological karyoarchitectonics which supplements the normal karyoarchitectonics (Bachmann, 1948). 6. The nuclear spheroids seem to be associated with increased neuronal activities, for their frequently strongly correlates with the neuronal hypertrophy which expresses enhanced neuroendocrinological activity.