FUNDAMENTAL AND APPLIED TOXICOLOGY 20, 15-22 (1993) The Effects of Feed Restriction on Reproductive Function in Swiss CD-1 Mice

Many test compounds used in toxicity studies produce a "sys-temic " toxicity manifested as reduced body weight gain. While it is known that reduced weight gain during juvenile growth reduces or delays reproductive competence, the effects of adult-onset feed restriction (FR) and inhibited weight gain on the re-productive system of mice are poorly known. To gain some in-formation on the effects of graded body weight reduction, or reduced body weight gain, on commonly used reproductive end-points, the studies reported below were conducted at two labo-ratories, using adult mice that were maintained at 90, 80, and 70 % of concurrent control body weight (CBW) for up to 21 weeks. Estrous cyclicity and fertility in the females were signif-icantly affected. While male fertility was variably affected, there was a significant decrease in the number of epididymal sperm and in the number of testicular spermatids in the 70 % CB