Extracorporeal Perfusion of the Human Foetus, Placenta and Foeto-Placental Unit

Lerner, U; Saxena, B.N.; Diczfalusy, E.

doi:10.1530/acta.0.069s310

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“…Proteins precipitable with trichloroacetic acid had a bi-exponential pattern, the half-times of release being 100 and 270 min. These rates of release indicate that the HCG produced by the early placenta was rapidly passed into the circulation rather than stored.Previous studies have established that HCG and proteins synthesized in vitro by placental tissue taken from women in the first trimester of pregnancy are secreted into the incubation media (Benagiano et al, 1972;Patrito et al, 1973).The rate of release of these macromolecules is not known and difficult to study in women in vivo, because the amount of radioactive material to be administered may be hazardous (Lerner et al, 1971). Moreover, the values may be a reflec¬ tion of maternal or fetal rather than placental function (Klopper, 1969).…”

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Secretion of Human Chorionic Gonadotrophin by the Early Placenta in Vitro

Patrito¹,

Flury²,

J³

et al. 1975

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The secretion in vitro of HCG and proteins was studied in fragments of placenta from women in the first trimester of pregnancy by a pulse-chase system. A 10-min pulse with [3H]leucine was used. It was concluded that the approximate half-time of release for HCG was 150 min. Proteins precipitable with trichloroacetic acid had a bi-exponential pattern, the half-times of release being 100 and 270 min. These rates of release indicate that the HCG produced by the early placenta was rapidly passed into the circulation rather than stored.Previous studies have established that HCG and proteins synthesized in vitro by placental tissue taken from women in the first trimester of pregnancy are secreted into the incubation media (Benagiano et al., 1972;Patrito et al., 1973).The rate of release of these macromolecules is not known and difficult to study in women in vivo, because the amount of radioactive material to be administered may be hazardous (Lerner et al., 1971). Moreover, the values may be a reflec¬ tion of maternal or fetal rather than placental function (Klopper, 1969). There¬ fore we have used the in-vitro pulse-chase system developed by Meldolesi et al. Samli &Lai (1973) to study the secretion of prolactin and growth hormone from rat pituitaries. The tissue is given a radioactive label for a short period of time, and the transport of a constant amount of radioactive molecule can be subsequently followed (Schramm, 1967). Placentae were obtained from five women in the first trimester of pregnancy after therapeutic abortion induced by curettage. Tissues were collected in cold Ringer solution and used within 1 hr. Fragments of each placenta, weighing approximately 5 to 10 mg, were washed several times with cold Krebs-Ringer bicarbonate, pH 7-2 (Krebs, 1950). Aliquots of 100 mg were placed in 15-ml Ehrlenmeyer flasks containing 1 ml Krebs-Ringer bicarbonate and 8 µ Ci L-[4,5-3H]leucine (sp. act. 41-2 Ci/mmol) (New England Nuclear Corporation).The flasks were left in a cold water-bath for 15 min and then pulse-labelled for 10 min at 37°C in an atmosphere of 95% C02/5% 02 in a shaking bath at 1*5 cycles/sec. The fragments of placenta were then separated from the radio¬ active incubation media, washed three times with large volumes of warm in-509

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confidence: 99%

“…The rate of release of these macromolecules is not known and difficult to study in women in vivo, because the amount of radioactive material to be administered may be hazardous (Lerner et al, 1971). Moreover, the values may be a reflec¬ tion of maternal or fetal rather than placental function (Klopper, 1969).…”

mentioning

confidence: 99%