[Electron microscopic study of rat tanicyte differentiation during the perinatal period]. / Electronno-mikroskopicheskoe issledovanie differentsirovki tanitsitov u krys v perinatal'nom periode.

The tanycyte differentiation during the perinatal period was studied by means of electron microscope in rats. From the 16th till the 18th day of prenatal period the wall of the 3rd ventricle is formed by intensively proliferating matrix cells with a narrow long apical process, oval perykarya and basal process. As the differentiation proceeds, the apical process shortens and disappears. The number of such cells increases gradually. At the same time the concentration of rough endoplasmic reticulum, mitochondria, polysomes, lipid droplets, dense, lamellated and multivesicular bodies increases. By the 3rd day the proliferative activity of cells decreases and they differ markedly in the ventral and ventrolateral parts of the infundibular recess and in the periphery of its broadened part. After the 5th day the ultrastructure of tanycytes and character of their distribution within the infundibular recess practically do not change, thus witnessing indirectly the completion of the main stages of differentiation of these cells.

[Changes in the amount of protein in hypothalamic neurons of sexually mature rats castrated neonatally]. / Izmenenie kolichestva belka v neironakh gipotalamusa polovozrelykh krys-samtsov, kastrirovannykh neonatal'no.

A change in the amount of protein in the neurons of the anterior and mediobasal hypothalamus of sexually mature male rats castrated neonatally was observed in the study using the interferometric method. A considerable increase was recorded in the dry weight of the neurons in the medial preoptic region and the arcuate and ventromedial nuclei of the hypothalamus. The most pronounced changes were observed in the nuclei of these neurons. The results obtained point to the influence of androgens on the hypothalamic structures responsible for the regulation of both cyclic and tonic release of gonadotropic hormones in sexually mature animals during sex differentiation of the brain.

[Determination of thyroxine and triiodothyronine in the thyroid glands of encephalectomized rat fetuses]. / Opredelenie tiroksina i triiodtironina v schchitovidnoi zheleze éntsefaléktomirovannykh zarodyshei krysy.

Concentration of thyroxin and triiodothyronine in the thyroid gland of encephalectomized and intact fetuses of rats with normal and prolonged gestation period was determined by means of isotope methods. Encephalectomy of 19-day old fetuses did not produce any significant effect on the concentration of thyroid hormones in the gland 2 and 4 days after the operation. The results obtained pointed to the absence of the hypothalamic control over the thyroid function in prenatal development of rats.