Tsvetkov T, Takeva T
Central Problem Laboratory for Cryobiology and Freeze-Drying, Sofia, Bulgaria.
Cryobiology. 1989 Aug;26(4):397-406. doi: 10.1016/0011-2240(89)90064-3.
The ovaries of 84 ground squirrels (C. Citellus L.) were studied during the four seasons of the year. The ovarian atretic follicles were examined by histological methods and by electron microscopy. The histoenzyme activities of NAD.H2-tetrazolium reductase, glucose-6-phosphate dehydrogenase, and 3 beta-hydroxy-delta 5-steroid dehydrogenase were photometrically demonstrated. The steroid-producing atretic follicles were mainly described as they reached their highest enzyme activity during the lactation period in April. The atresia of the primordial and primary follicles was manifested by disappearance of the oocyte and preservation of the granulose cells surrounded by basal lamina. Atresia of follicles with two oocytes was a typical process for the ground squirrel. Later on the oocytes and the granulose cells around it disappeared. The remaining part of the follicle continued its development and reached maturity. Atresia was observed mainly in March, April, and May.
对84只地松鼠（C. Citellus L.）的卵巢在一年的四个季节进行了研究。通过组织学方法和电子显微镜检查卵巢闭锁卵泡。用光度法显示了NAD.H2-四唑还原酶、葡萄糖-6-磷酸脱氢酶和3β-羟基-δ5-类固醇脱氢酶的组织酶活性。主要描述了产生类固醇的闭锁卵泡，因为它们在4月哺乳期达到最高酶活性。原始卵泡和初级卵泡的闭锁表现为卵母细胞消失，而被基膜包围的颗粒细胞得以保留。有两个卵母细胞的卵泡闭锁是地松鼠的典型过程。随后，卵母细胞及其周围的颗粒细胞消失。卵泡的其余部分继续发育并成熟。闭锁主要在3月、4月和5月观察到。
