Blood Reservoir Function of the Fetal Guinea Pig Liver
To determine of the fetal liver functions as a blood reservoir, we measured liver blood volume under normal conditions and after hemorrhage and volume loading. Nineteen pregnant guinea pig sows and 54 near-term fetuses were injected intravenously with 51Cr-labeled red cells while the fetuses remained in utero. Ninety seconds later a 0.5-1.0 g sample of liver was garroted with a sharp wire into a tared tube with minimal blood loss. A blood sample was taken to measure counts per ml of blood, the fetus killed and the remainder of the liver weighed. Blood volume of the liver and body were calculated. Groups of fetuses were studied with normal volume, after 14% hemorrhage and 12% volume loading. Adult sows weighed 1235 ± 29 (SEM) g with a blood volume of 60.4 ± 2.3 ml, of which the liver contained 11.2 ± 0.5 ml. Fetuses weighed 58.2 ± 1.8 g. Under normal conditions fetal blood volume was 5.1 ± 0.2 ml and the liver contained 22.7 ± 1.8% of total blood volume. This fell to 16.9 ± 1.6% after hemorrhage, but did not change significantly from normal during volume loading. These results indicate the fetal liver is relatively larger than the adult and contains more blood per gram of tissue. Following decreases in blood volume the fetal liver acts as a blood reservoir by releasing blood into the circulation. It releases a volume equal to about 60% of the shed blood after a moderate hemorrhage.
Obstetrics and Gynecology, Pathology, Veterinary Physiology, Blood Volume; Liver Function Tests; Guinea Pigs -- physiology
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