Placental transfer and metabolism of purines and nucleosides in the pregnant guinea pig

Kreel, B.K. van; Dijk, J.P. van; Pijnenburg, A.M.C.M.

doi:10.1016/s0143-4004(82)80046-5

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…The exception to this is that GUAase was not expressed by any of the cell types in the reproductive tract. Consistent with the lack of guanase expression by the decidual cell types, and our proposal that the role of the catabolic enzymes is to metabolize large quantities of nucleosides generated in situ, Van Kveel (1982) has observed that both uric acid and guanine accumulate in amniotic fluid. Expression of the catabolic enzymes may be especially critical in the early postimplantation period as Knudsen et al (1989) have shown that the inhibition of ADA activity at day 7 or 8 p.c., but not at day 6 or 9 causes pronounced embryolethality with neural plate cell degeneration.…”

Section: Reproductive Tract Expressionsupporting

confidence: 87%

Coordinate developmental regulation of purine catabolic enzyme expression in gastrointestinal and postimplantation reproductive tracts.

Witte

Wiginton

Hutton

et al. 1991

The Journal of Cell Biology

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Abstract. Using histochemical detection, we have visualized in situ the complete metabolic pathway for the degradation of purine nucleotides. From the tongue to the ileum, diverse epithelial cell types lining the lumen of the mouse gastrointestinal (GI) tract strongly coexpress each of the five key purine catabolic enzymes. Dramatic increases in the expression of each enzyme occurred during postnatal maturation of the GI tract. Using in situ hybridization, an intense accumulation of adenosine deaminase (ADA) mRNA was detected only within GI epithelial cells undergoing postmitotic differentiation . In a similar manner, at the developing maternal-fetal interface, high level expression of the purine catabolic pathway also occurred in a unique subset of maternal decidual cells previously known to express high levels of alkaline phosphatase P URINE nucleotide synthesis and degradation are essential for life. Genetic defects in the purine metabolic pathway can cause devastating human disease, such as Lesch-Nyhan syndrome or severe immunodeficiency (Giblett, 1972; Camera and Carson, 1987 ;Kredich and Hershfield, 1989) . The importance of the purine pathway is also illustrated by the wide variety of potent and clinically beneficial drugs such as allopurinol, 6-mercaptopurine, methotrexate, and trimethoprim that have resulted from pharmacological targeting of purine pathway enzymes (for review, see Elion, 1989). The purine ring, large quantities of which are required for cell growth and proliferation, requires for its synthesis more than a dozen enzyme activities, a spectrum of metabolic substrates, and a substantial amount of chemical energy.Given the metabolic expense of purine biosynthesis, it might be considered surprising that mice and other mammals do not reuse dietary purine nucleotides for DNA and RNA synthesis (Sonoda and Tatibana, 1978 ;Ho et al., 1979;Savaiano et al., 1980 ;Uauy, 1989). Consistent with this, rat duodenal mucosa has long been shown to produce the nonreusable purines, uric acid and allantoin, from AMP (Getler

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Section: Reproductive Tract Expressionsupporting

confidence: 87%

Coordinate developmental regulation of purine catabolic enzyme expression in gastrointestinal and postimplantation reproductive tracts.

Witte

Wiginton

Hutton

et al. 1991

The Journal of Cell Biology

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“…Furthermore, transplacental tritium was represented primarily by metabolic products suggesting that adenosine does not normally reach the fetal circulation intact and is not a candidate for materno-fetal exchange. These results confirm previous findings in the perfused guinea-pig placenta in which [3H]adenosine metabolites accounted for greater than 95 % of the activity recovered in the opposite circulation (Van Kreel et al 1982).…”

Section: Transplacental Transfersupporting

confidence: 92%

“…These results again stress the high adenosine degrading capacity of the fetal side ( Fig. 2) and confirm the presence of xanthine oxidase in the guinea-pig placenta (Van Kreel & Van Dijk, 1977;Van Kreel et al 1982).…”

supporting

confidence: 79%

“…Our results also show that, within comparable time periods, the fetal side of the guinea-pig placenta appears to have a greater capacity for adenosine degradation than the microvillous border. This asymmetry was not reported during steady-state perfusion of [3H]adenosine in a similar preparation (Van Kreel et al 1982). However, our results agree qualitatively with those of Van Kreel et al (1982) insofar as [3H]inosine was a major constituent of the venous effluent.…”

Section: Adenosine Metabolismmentioning

confidence: 76%

“…This asymmetry was not reported during steady-state perfusion of [3H]adenosine in a similar preparation (Van Kreel et al 1982). However, our results agree qualitatively with those of Van Kreel et al (1982) insofar as [3H]inosine was a major constituent of the venous effluent. Rapid formation of inosine and hypoxanthine from labelled adenosine has also been observed within a single transit through other capillary beds including heart (Sparks et al 1985), lung (Bakhle & Chelliah, 1983;Hellewell & Pearson, 1983;Catravas, 1984) and skeletal muscle (Gorman et al 1986).…”

Section: Adenosine Metabolismmentioning

confidence: 76%

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Transport and metabolism of adenosine in the perfused guinea‐pig placenta.

Wheeler

Yudilevich

1988

The Journal of Physiology

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SUMMARY1. Uptake and metabolism of adenosine were investigated from both maternal (M) and fetal (F) circulations of the isolated, dually perfused guinea-pig placenta by using a single-circulation paired-tracer ([14C]sucrose as extracellular reference, and [3H]adenosine) dilution technique.2. Maximal [3H]adenosine uptakes (percentage of dose) from adenosine-free perfusates were 75+1 and 87+2% (mean+S.E. of mean) at maternal and fetal blood-tissue interfaces respectively. Rapid backflux (percentage of influx) of tritium (labelled adenosine and/or adenosine derivatives) from the placental tissue into the ipsilateral circulation was higher at the fetal (24 + 2 %) than at the maternal side (11+2%).3. Tritium uptakes were reduced to 50 + 4 (M) and 60 + 6 % (F) when the perfusion medium contained 100 ,IM-unlabelled adenosine; backflux was highly stimulated (44 % M and 84 % F). Neither uptake nor backflux were affected by inosine, uridine, adenine or hypoxanthine present in the perfusion medium (1 mM).4. Tissue sequestration of tritium (5-6 min) was approximately 60% of the injected dose when perfusates were adenosine-free and 20 % or less in the presence of 100 /IM-adenosine. 9. The present data demonstrate DIP-and NBMPR-sensitive carrier-mediated adenosine uptake at the brush-border side of the syncytiotrophoblast (maternalfacing) and at the fetal side. In the latter case the role of the basal syncytial membrane and the fetal endothelium could not be distinguished. Rapid metabolism of adenosine also occurs at both blood-tissue interfaces. The placenta may therefore be involved in the regulation of adenosine-related functions in mother and fetus during pregnancy.

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Highest ADA Expressing Mouse Tissues Also Exhibit Cell-Type Specific Coordinate Up-Regulation of Purine Degradative Enzymes

Aronow

Witte

Wiginton

et al. 1991

Advances in Experimental Medicine and Biology

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Placental transfer and metabolism of purines and nucleosides in the pregnant guinea pig

Cited by 9 publications

References 11 publications

Coordinate developmental regulation of purine catabolic enzyme expression in gastrointestinal and postimplantation reproductive tracts.

Coordinate developmental regulation of purine catabolic enzyme expression in gastrointestinal and postimplantation reproductive tracts.

Transport and metabolism of adenosine in the perfused guinea‐pig placenta.

Highest ADA Expressing Mouse Tissues Also Exhibit Cell-Type Specific Coordinate Up-Regulation of Purine Degradative Enzymes

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