[Morphometric characteristics of the development of the neurosecretory cells in the hypothalamic center in the rat during postnatal ontogeny].

Neurosecretory cells has been studied in the supraoptic and paraventricular hypothalamic nuclei and in the additional anterocommissural group in rats at 17-80 days of the postnatal development. The cellular functional activity is estimated according to neurosecretion contents in the pericaryon and according to the state of the nucleolar apparatus (volume, amount and position of the nucleoli in the nucleus). The neurosecretory cells complete their formation only by the end of the second postnatal month. The neurosecretory cells of the three hypothalamic centers studied differ by the character of their development. The development of the neurosecretory cells of the anterocommissural group differs considerably from that of the paraventricular and supraoptic nuclear neurosecretory cells, that supports the suggestion about their independent functional role. During the investigation performed especially sharp shifts in the state of the neurosecretory system are noted in the young rats at the age of about 30 days.