Greatinine Equilibrium Between Mother and Nephrectomized Primate Fetus. ∗

Summary and conclusions

1. Concentrations of creatinine in maternal and fetal sera of the monkey are within the range considered normal for pregnant humans. 2. Concentrations of creatinine in maternal and fetal sera remain in equilibrium and within this normal range 3 and 4 weeks after bilateral fetal nephrectomy. 3. It is not necessary to postulate renal excretion of creatinine into the amniotic fluid and subsequent absorption or diffusion by the chorioamniotic membrane to account for creatinine equilibrium between fetus and mother. 4. It is suggested that the placenta, rather than the fetal kidneys, is important in maintaining the composition of fetal serum.