scholarly journals Reduction of biliverdin and placental transfer of bilirubin and biliverdin in the pregnant guinea pig

1981 ◽  
Vol 194 (1) ◽  
pp. 273-282 ◽  
Author(s):  
A F McDonagh ◽  
L A Palma ◽  
R Schmid
Keyword(s):  
Guinea Pig ◽  
Placental Transfer ◽  
Reductase Activity ◽  
Maternal Circulation ◽  
Biliverdin Reductase ◽  
Maternal Liver ◽  
Placental Transport ◽  
Guinea Pig Placenta ◽  
Pig Placenta ◽  
Efficient Elimination

Biliverdin was reduced to bilirubin in pregnant and foetal guinea pigs, and the 100000 g supernatant from homogenates of foetal liver, placenta and maternal liver showed high biliverdin reductase activity. The placental transport of unconjugated bilirubin and biliverdin was compared by injecting unlabelled and radiolabelled pigments into the foetal or maternal circulation and analysing blood collected from the opposite side of the placenta. Injected bilirubin crossed the placenta from foetus to mother and vice versa, but injected biliverdin did not appear to cross without prior reduction to bilirubin. The guinea-pig placenta is apparently more permeable to bilirubin than biliverdin. Reduction of biliverdin to bilirubin in the foetus may, therefore, be essential for efficient elimination of haem catabolites from the foetus in placental mammals.

PLACENTAL TRANSFER OF 131I-LABELLED IODIDE IN THE GUINEA-PIG

1964 ◽  
Vol 28 (3) ◽  
pp. 247-252 ◽  
Author(s):  
W. T. LONDON ◽  
W. L. MONEY ◽  
R. W. RAWSON
Keyword(s):  
Guinea Pig ◽  
Placental Transfer ◽  
Sodium Thiocyanate ◽  
Perfusion Technique ◽  
Maternal Circulation ◽  
Guinea Pig Placenta ◽  
Small Discharge ◽  
High Concentrations ◽  
Pig Placenta

SUMMARY The transfer of radioactive iodide (131I) across the guinea-pig placenta has been investigated, using an in situ perfusion technique. From these studies, it can be concluded that iodide is actively transported from the maternal side to the foetal side of the placenta, and is concentrated on the foetal side. Radio-iodide accumulates on the foetal side because the foetal placenta concentrates iodide from the maternal circulation and transfers little to the maternal circulation. High concentrations of stable iodide perfused on the foetal side did not affect the transfer of radio-iodide from the maternal circulation to the foetal side of the placenta. Sodium thiocyanate, on the other hand, blocked the concentration of iodide on the foetal side, and caused a small discharge of radio-iodide from the placenta.

scholarly journals Maternal 3,3’-Diiodothyronine Sulfate Formation from Guinea Pig Placenta Perfused with 3,3’,5-Triodothyronine

2021 ◽  
Vol 5 (7) ◽  
pp. 01-06
Author(s):  
Sing-yung Wu ◽  
Charles H. Emerson ◽  
Edward Tjioe ◽  
Dong-bao Chen
Keyword(s):  
Thyroid Hormone ◽  
Guinea Pig ◽  
Maternal Serum ◽  
Late Gestation ◽  
Outer Ring ◽  
Maternal Transfer ◽  
Maternal Circulation ◽  
Guinea Pig Placenta ◽  
Pig Placenta

Objective: Serum 3, 3’,5-triiodothyronine (T3) remains low in near-term fetus to prevent the growing fetus from undue exposure to its active catabolic effect in mammals. The present study was undertaken to gain insight in the role of placenta in T3 metabolism, fetal to maternal transfer of T3, and its metabolites by in situ placenta perfusion with outer-ring labeled [125I]-T3 in pregnant guinea pig, a species showing increased sulfated 3, 3’-diiodothyronine (T2S) levels in maternal serum in late pregnancy (term = 65 days), similarly to humans in pregnancy. Materials and Methods: One-pass placenta perfusions performed on pregnant guinea pigs were studied between 58 - 65 days of gestation. In two separate experiments, the umbilical artery of the guinea pig placenta was perfused in situ at 37°C with outer-ring labeled [125I]-T3. Maternal sera and umbilical effluents were obtained for analysis at the end of a 60-minute perfusion, when the steady-state levels of radioactivity were reached in the placenta effluent after 30-minute. Results: Sulfated [125I]-T2S was readily detected in the maternal serum as the major metabolite of T3 following the perfusion of placenta with [125I]-T3, suggesting that placental inner-ring deiodinase and sulfotransferase may play an important role in fetal T3 homeostasis and in the fetal to maternal transfer of sulfated iodothyronine metabolites. Conclusions: The expression of type 3 deiodinase (D3) and thyroid hormone sulfotransferase activity in placenta may play an important role to protect developing organs against undue exposure to active thyroid hormone in late gestation in the fetus. The combined activities of D3 and sulfotransferase promoted a placental transfer of T2S into maternal circulation. The maternal circulation of T2S is fetal T3 in origin and its role as a fetal thyroid function biomarker deserves further evaluations and studies.

Multidrug resistance phosphoglycoprotein (ABCB1) expression in the guinea pig placenta: developmental changes and regulation by betamethasone

2009 ◽  
Vol 87 (11) ◽  
pp. 973-978 ◽  
Author(s):  
Grazyna M. Kalabis ◽  
Sophie Petropoulos ◽  
William Gibb ◽  
Stephen G. Matthews
Keyword(s):  
Guinea Pig ◽  
Preterm Labour ◽  
Treatment Strategies ◽  
Late Gestation ◽  
Maternal Circulation ◽  
Fetal Protection ◽  
Guinea Pig Placenta ◽  
Mrna And Protein Expression ◽  
Pig Placenta ◽  
Synthetic Glucocorticoids

Placental ABCB1 plays an important role in fetal protection against xenobiotics in the maternal circulation. Limited evidence indicates that glucocorticoids regulate ABCB1 expression in other tissues. Since approximately 10% of pregnant women are treated with synthetic glucocorticoids for threatened preterm labour, the effects of synthetic glucocorticoids on placental ABCB1 are important. We hypothesized that placental levels of ABCB1 are reduced in late gestation in the guinea pig and that synthetic glucocorticoids downregulate ABCB1 production. There was a significant decrease in placental Abcb1 mRNA expression in late gestation. Treatment of guinea pigs with betamethasone (1 mg/kg) on gestational days 40/41 and 50/51 resulted in a significant decrease in placental Abcb1 mRNA and protein expression. No sex differences were observed. Understanding the regulation of ABCB1 function will facilitate the development of treatment strategies for human fetal protection against maternally derived endobiotics and xenobiotics.

Placental calcium and phosphorus transfer in the guinea pig: lack of effect of modulators of Ca-ATPase and alkaline phosphatase activity

1983 ◽  
Vol 61 (11) ◽  
pp. 1354-1360 ◽  
Author(s):  
H. G. McKercher ◽  
L. O. Derewlany ◽  
I. C. Radde
Keyword(s):  
Alkaline Phosphatase ◽  
Guinea Pig ◽  
Placental Transfer ◽  
Placental Perfusion ◽  
Perfusion Solution ◽  
Guinea Pig Placenta ◽  
Calcium And Phosphorus ◽  
Pig Placenta

The effects of modulators of Ca-ATPase and alkaline phosphatase (AP) activity on placental calcium and phosphorus transfer were studied using the in situ perfused guinea pig placenta. The diuretics ethacrynic acid and furosemide had no significant effect on placental calcium and phosphorus transfer when injected into the mother (1.0 or 10.0 mg∙kg−1) or added to the solution perfusing the fetal side of the placenta (0.25 or 2.0 mM). These two drugs have previously been shown to inhibit placental Ca-ATPase and enhance AP activity in vitro. D-Penicillamine, which inhibits placental AP but not Ca-ATPase activity in vitro, also had no significant effect on net calcium and phosphorus transfer from mother to fetus either when given to the mother (50 mg∙kg−1) or added to the placental perfusion solution (0.25 or 2.0 mM). These results suggest that placental transfer of calcium and phosphorus in the guinea pig may not be directly related to placental Ca-ATPase and AP activities.

Transfer of lipids across the guinea pig placenta

1969 ◽  
Vol 104 (4) ◽  
pp. 564-572 ◽  
Author(s):  
Herbert J. Kayden ◽  
Joseph Dancis ◽  
William L. Money
Keyword(s):  
Guinea Pig ◽  
Guinea Pig Placenta ◽  
Pig Placenta
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