The metabolism of the isolated artificially perfused guinea pig placenta I. Excretion of hydrogen ions, ammonia, carbon dioxide and lactate, and the consumption of oxygen and glucose

The metabolism of the isolated artificially perfused guinea pig placenta. II. Difference of excretion of hydrogen ions, ammonia, carbon dioxide and lactate into maternal and fetal veins

“…The concentration of ammonia is measured with a special ammonia electrode (PHI-LIPS Ammoniak Elektrode). Excretion and utilization rates in this paper are given äs l O" 6 mol X g" 1 X min" 2 and lactate increases, s At nearly the same flow ratio, but twice the total described in a previous paper, when the perfusion flow, the excretion increases significantly on both flow increases [3]. Of importance is not only the sides (Tab.…”

“…In a previous paper we could demonstrate for the isolated, dually perfused guinea pig placenta the consumption of glucose and oxygen and the production of H+, NH 3 , lactate and C0 2 for at least 90 minutes [3]. In all experiments the excretion rates on the maternal side exceed those of the fetal side (Tab.…”

“…I). The utilization of oxygen and glucose have been determined [3] äs follows: .51 ± .11 oxygen and .35 ± .25 glucose. The uptake of oxygen and glucose is also higher from the maternal than from the fetal vessels: 57% of utilized oxygen and 72% of utilized glucose arise from the maternal side.…”

“…Further details of preparation and perfusion technique have been described previously [3,9,13]. The perfusion fluid is saturated with 95% 0 2 and 5% C0 2 , the pH is maintained at 7.40.…”

“…The isolated, on the maternal and fetal side artificially perfused guinea pig placenta produces for at least 90 minutes hydrogen ions, ammonia, lactate and carbon dioxide and consumes glucose and oxygen [3]. Because the maternal and fetal metabolism are excluded, this model is appropriate for studying transport problems through the placental membranes.· The guinea pig placenta is often used, because it is like the human a hemochorial placenta.…”