FOOD-RESTRICTED, PREPUBERTAL, FEMALE RATS - RAPID RECOVERY OF LUTEINIZING-HORMONE PULSING WITH EXCESS FOOD, AND FULL RECOVERY OF PUBERTAL DEVELOPMENT WITH GONADOTROPIN-RELEASING-HORMONE

Prepubertal female rats were maintained continuously at 45% of their expected 50-day body weight by restricting their food intake. Uteri and ovaries declined in weight under these conditions. No evidence of pulsatile LH release was seen when these animals were examined at 50 days of age. Allowing unlimited access to food at this time caused rapid pubertal development. LH pulsing began in some females within 12 h; strong LH pulsing was seen in most females within 24 h, and all ovulated after only 2 1/2 or 3 1/2 days of ad libitum feeding. These were fertile ovulations, accompanied by mating and resulting in pregnancy. Administering GnRH in a pulsatile manner to 50-day-old, food-restricted animals also yielded full pubertal development. Uteri and ovaries gradually increased in weight, and ovulation occurred in 3 1/2 to 5 1/2 days. These findings support a contention that the major reproductive deficit resulting from food restriction relates to the control of GnRH secretion. In toto they also suggest a close metabolic coupling between some dimension of nutrient and/or energy processing and the GnRH pulse generator in the normally growing female.