Evidence of increased fatty acid transfer across the placenta during a maternal fast in rabbits.

Fetal rabbits were obtained by Caesarian section from 28-day pregnant does which had been fasted for 48 h (days 26-28). Organ weights, fat contents and blood metabolite levels were compared with a group obtained in a similar manner from non-fasted does. Similar data were obtained for term fetuses (31 days) born by natural delivery. In 28-day pregnant, fasted does, blood levels of free fatty acids (FFA) and glycerol were doubled compared with non-fasted controls. Fetal levels showed a similar increase. Both groups of fetuses from fasted does had increased fat stores both in the liver and adipose tissue. The overall increase in fat stores was 80-100%. It is suggested that during maternal fasting increased amounts of maternal FFA cross the placenta into the fetal circulation and are incorporated into the fetal fat stores.