[Histomorphology of the suslik ovary during postnatal development and hibernation]

Morphogenetic and histogenetic changes in the ovaries of Citellus citellus during the postnatal period and hibernation (September- March) at the age of 10, 25, 45 days and 2 to 12 months after birth were studied. Significant cellular and tissue-organoid differentiation processes were established. After birth oogonia enter the prophase I of meiotic division. At the end of the first month, oocytes with enlarged cytoplasm and single layer of satellite cells form the primary follicles. The growing follicles with organizing antrum are formed in the third postnatal month. During the same time, theca foliculi is observed. Between the 3d and the 6th months after birth the authors demonstrate a "stage ox isofolliculia" when the follicles stop undergoing further development. During the winter hibernation, the ovarian follicles continue to grow slowly and at the end of this period, preovulatory follicles are formed. The results reported demonstrate Citellus citellus ovary to be an organ of intensive cell-tissue reconstruction during the postnatal development and hibernation period determined by the ovarian histophysiology, the ovarian steroid hormones production and the hormonal activity of other glands and organs of the endocrine system.