[The influence of weight loss on the reproductive function of the female rat: changes in the estrous cycle and hypothalamo-pituitary-ovarian function during feed restriction and subsequent refeeding period].
Twelve-week-old female SD rats were restricted to an 8 g/day feed intake for 2 months followed by feeding ad libitum for 3 weeks. Feed restriction resulted in weight loss and constant diestrous. A persistent increase in the hypothalamic GnRH content was observed during the underfed period. Serum LH and PRL levels dropped throughout the period but the initial reduction in the serum FSH level was observed on the 60th day. The reductions in the pituitary content of these hormones were observed on the 30th day. The decrease in the serum and ovarian E2 levels were detected on the 14th day. Anterior pituitary showed a significant response to GnRH + TRH during the course, and the relative increases in LH, FSH and PRL were greater than those in the pretreatment rats. In the course of refeeding, the body weight returned to the control level and regular estrous cycles were reestablished on the 15th and 21st day, respectively. Elevated hypothalamic GnRH content returned to the control level on the 16th day. The changes in the pituitary-ovarian axis were prompt rebound rises in serum FSH and PRL levels and pituitary FSH content, delayed restoration of serum and pituitary LH levels and serum and ovarian E2 levels, and a marked increase in the serum and ovarian progesterone levels on the 16th day. The relative increases in FSH and PRL after GnRH + TRH injection were smaller than those in the underfed period.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D001835:Body Weight; D004435:Eating; D004967:Estrogens / Q000032:analysis; D004971:Estrus; D005260:Female; D005502:Food; D005508:Food Deprivation; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis; D006065:Gonadotropins, Pituitary / Q000032:analysis; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007031:Hypothalamus / Q000032:analysis; D010053:Ovary / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D004967:Estrogens; D006065:Gonadotropins, Pituitary; D007987:Gonadotropin-Releasing Hormone