Maternal hypoxia reduces the availability of oxygen to the fetus, a reduction accompanied by decreased protein synthesis and reduced protein accretion. However, there is no evidence to show whether these effects are unique to maternal hypoxia or also occur when fetal oxygen availability is reduced by other means. To find if maternal anemia, a condition that also decreases fetal oxygen availability affects fetal protein metabolism, we measured fetal protein metabolism by infusion of 1-14C-leucine in seven chronically prepared fetal sheep. Following control measurements, the ewes' hematocrit was reduced from 31.7±1.5% to 12.3±0.4% by isovolemic exchange transfusion. The decreased fetal oxygen availability associated with maternal anemia affected fetal leucine metabolism in a manner somewhat different than that previously reported for maternal hypoxia. Both conditions decreased fetal leucine uptake. Oxidation of leucine fell during maternal anemia, an effect not reported during maternal hypoxia. Fetal protein metabolism was also affected slightly differently. Maternal anemia reduced not only protein synthesis (an effect reported during maternal hypoxia) but also decreased fetal protein breakdown. Regardless of the method used to decrease oxygen availability, fetal protein accretion fell, a finding incompatable with normal fetal growth. Table

Table 1
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