The Distribution and Metabolism of C14-Labeled Lactic Acid and Bicarbonate in Pregnant Primates *

Exchange of carbon dioxide in the pregnant rhesus monkey: multicompartmental analysis of carbon dioxide kinetics

“…This appears to be justified because under relatively constant conditions the rate of COa fixation by either the fetal or maternal tissue would be insignificantly low compared to the rate of COs production. Judging from the findings that the metabolic rate based upon the rate of CO, production by the fetal monkey in our study is similar to that based upon O2 consumption by the newborn monkey found by Dawes et al which was measured quite accurately because of the technical feasibility in the newborn animal, and that all the fetuses in our study survived with normal heart rates for [5][6][7][8][9][10][11][12][13][14] days after the experiment, we believe that the condition of our fetuses was within the physiological limit. How Since we know all compartments exchange with each other, we set up the model as the following one,…”

“…Their studies indicate the existence of at least three compartments regarding the distribution of the bicarbonate. The previous reports from this laboratory by Friedman et al (11) and Plentl and Friedman (12) have given evidence that in the pregnant animal there are several distinct compartments such as maternal blood, maternal extravascular pool, fetal blood, fetal extravascular pool, and amniotic fluid with regard to the distribution of acid-volatile '4CO2 after the injection of bicarbonate-"4C. Furthermore such an assumption is consistent with the present data which can be clearly broken down into at least three exponential components (Figs.…”

“…A study of the carbon dioxide transfer using "C in the rhesus monkey has been previously conducted in this laboratory (11,12). Although it yielded only qualitative interpretation of the time-activity curves, the study indicated that the isotope distribution technique was perhaps the most promising in the quantitation of C02 transfer across the placenta.…”

Fetal insulin and growth hormone metabolism in the subhuman primate

“…The experimental technique involved cannulation of, and blood sampling from, interplacental fetal vessels in the pregnant monkey (Macaca mulatta). The use of this animal as a model for placental transfer and fetal metabolic studies has been previously described (10)(11)(12)(13). In an attempt to define any modifying influence of the placenta on fetal plasma responses, the bidirectional placental transfer of radioisotopically labeled insulin, and the neonatal plasma responses to the same stimuli were examined.…”

Accumulation and disappearance of lactate in a fetus with a hemochorial placenta. The role of placental transfer and fetal metabolism.

“…In sheep and other species with an epitheliochorial placenta which is virtually impermeable for lactate [12] the rate of accumulation and disappearance seems to be determined only by the rate of fetal lactate production and utilisation. In man, however, and other species with a hemochorial placenta which is well permeable for lactate [4,6] the placental transfer is expected to slow down the rate of accumulation of lactate and to speed up the rate of disappearance. Thus, the rate of accumulation and disappearance of lactate in a fetus with a hemochorial placenta is determined by the rate of both fetal metabolism and placental transfer.…”