In-vivo and in-vitro studies on the effects of maternal fasting during embryonic organogenesis in the rat.

Pregnant rats were fasted for periods of 6, 12, 24 or 36 h terminating at 10 1/2 days post coitum (p.c.); virgin rats were fasted concurrently. Both groups showed similar loss of body weight and fall in serum glucose levels. Embryos from rats which were fasted for 12 h or longer showed retarded growth and differentiation compared with embryos from non-fasted animals. Another group of rats, similarly fasted for periods before 10 1/2 days p.c. were then fed ad libitum until 15 1/2 days p.c.; the fetuses were smaller than fetuses of similar age from non-fasted rats. Embryos from fed mothers were explanted at 9 1/2 days p.c. and cultured for 45 h in rat serum prepared from fed or fasted animals. Embryonic development was retarded in the serum from fasted rats unless glucose was added to raise the glucose level to that of normal serum.