THE EFFECTS OF TOTAL-BODY X-IRRADIATION ON THE 

 REPRODUCTIVE GLANDS OF INFANT FEMALE RATS 



D. SLADIC-SIMIC, N. ZIVKOVIC, D. PAV16, and 

 P. N. MARTINOVITCH 



Institute of Nuclear Sciences, " Boris Kidric" , Beograd, Yugoslavia 



SUMMARY 



For the study of the effects of total-body X-ray irradiation on the reproductive glands 

 of infant rats, 8- and 17 -day-old females were irradiated with doses of 400 r, 200 r, 100 r 

 and 50 r. Three-month-old adult females, servmg as controls, were irradiated with doses 

 of 400 r and 200 r. The effects of the various doses upon the reproductive glands, starting 

 with the prepubertal period up to the first ovulation were checked by the method of 

 counting the germ cells; by counting the mitotic divisions within the folUcles; by measiu*- 

 ing the volume of the ovaries; and by observing the fertHity of the exposed rats as weU as 

 their F^ and F,_, generations. 



The reproductive glands of 8-day-old rats proved to be most sensitive to X-ray 

 exposure. Less sensitive are those of 17-day-old rats, whereas the ovaries of 3-month-old 

 irradiated rats are least sensitive. In 8-day-old rats irradiation with a dose of 100 r 

 causes destruction of a large number of primary oocytes, but an accelerated development 

 of a few of them. A dose of 50 r will induce the growth of a large number of foUicles and 

 thus reduce the existing number of primary oocytes. As a result, the litter size at first 

 partuition of irradiated rats is larger than in controls. The F^ and Fo generations of the 

 exposed females show a high percentage of dwarfism and mortahty. 



The mammalian ovaries are very sensitive to ionizing radiation. Total- 

 body exposure to a dose of 400 r sterilizes adult mice in a few weeks (Russell 

 and Russell, 1956). The X-ray sterility effects in adult organisms are due to 

 the destruction of primary oocytes a few days after irradiation (Mandl, 1959). 

 Their sensitivity depends on the age of the irradiated animals. According to 

 the published data on mice, the primary oocytes are most sensitive in the 

 second and the third week post-partum, and more resistant during the first 

 few days after birth (Peters, 1961; Russell et al., 1959) and also in adult 

 organisms (Mandl, 1959). The sterilizing dose for infant rats has not yet been 

 determined. Few data concerning the differences in the effects of sterilizing 

 and sub-sterilizing doses on the ovaries have been published so far. We made 

 an attempt to determine the sterilizing X-ray doses for infant rats of different 

 ages and to foUow the effects of irradiation on the histological picture of the 

 ovaries. We assumed that the effect of X-irradiation on primary oocytes may 

 range from killing them outright to causing lasting injuries which find their 



327 



