The effect of restricted food intake and refeeding on the ovarian follicle population of the pre-puberal Wistar rat.

A 50 p. 100 restriction of food intake in female Wistar rats from day 21 to day 42 of life prevented ovulation and altered the size distribution and numbers of ovarian follicles. The rate of atresia of non-growing oocytes in primordial follicles was retarded resulting in more oocytes per ovary. The number of follicles initiated to grow was reduced. Semi-starved rats allowed free access to food from day 42 of life achieved the body weight of ad libitum-fed controls at 66 days of age. A delayed puberty occurred. The numbers of non-growing oocytes in primordial follicles per ovary declined but remained significantly greater than control values at 66 days of age. Refeeding increased the numbers of follicles undergoing growth but within the size distribution found in age-matched controls. Thus semi-starvation followed by refeeding rendered the ovary developmentally younger but only in terms of total oocyte numbers. The ovarian response to starvation and refeeding is discussed in relation to pituitary function and provides new information on the potential lability of the oocyte population.