Protein synthesis in rat maternal and fetal tissues with starvation

The incorporation a of 3H-leucine was studied in male rats and female rats 14 and 19 days pregnant that were either fed or starved for 48 hours. 3H-leucine incorporation into the liver was similar among all the fed animals. There was a 40% to 50% increase in the 3H-leucine incorporation of the placenta and fetus per milligram of ribonucleic acid from the fourteenth to the nineteenth day of pregnancy. With starvation there was a significant increase in 3H-leucine incorporation in both the fetus and the placenta of the 19-day-pregnant animal associated with a significant decrease in liver incorporation. Yolk sac placenta demonstrated a greater increase than the allantoic placenta. Both the male and 14-day-pregnant animals had minimal changes with starvation. The problems inherent in studying protein synthesis, especially during pregnancy, are presented.