Evidence for a specific transport of D-hexoses across the human term placenta in vitro

Carstensen, M. H.; Leichtweiß, H. P.; Molsen, G.; Schröder, H.

doi:10.1007/bf00717597

Cited by 40 publications

(10 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, given the small size of these vesicles, uptake measured at 15 sec would probably no longer be linear (Hopfer, 1978) so that uptake of D-glucose at the initial rate most likely exceeds that of L-glucose to a much greater extent. These same authors (Carstensen et al, 1977) reported that phloretin in a concentration of 1 mM reduced net D-glucose transport to 0.4 of the control value, which is qualitatively similar to what we have seen (Table 2).…”

Section: Discussionsupporting

confidence: 82%

“…Thus, Carstensen et al (1977) in a perfused preparation found D-glucose transport to be 2.4-2.7 times that of L-glucose, a value similar to what we have observed in the plasma membrane vesicle preparation (see Fig. 2).…”

Section: Discussionsupporting

confidence: 71%

“…This observation is consistent with partial saturation of a carrier mechanism. Artificially perfused human placental studies have shown in vitro that glucose transfer is stereospecific (Carstensen, Leichtweiss, Molsen & Schr6der, 1977), that D-glucose transfer can be competitively inhibited by Dmannose (Carstensen et al, 1977) and 3-O-methyl-e-D-glucopyranoside , and that counter transport of glucose may be demonstrated ). In addition, glucose transport showed saturation kinetics although this finding could not be confirmed in a subsequent study (Carstensen et al, 1977).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Glucose uptake into plasma membrane vesicles from the maternal surface of human placenta

et al. 1981

View full text Add to dashboard Cite

Glucose uptake into plasma membrane vesicles from the maternal surface of the human placenta was measured with the Millipore filtration technique. Uptake off D-glucose was dependent on the osmolarity of the incubation medium surrounding the vesicles. Uptake of D-glucose exceeded that of L-glucose. The uptake of D-glucose was not enhanced by placing 100 mM NaCl or NaSCN in the medium outside the vesicles (none inside) at the onset of uptake determinations. D-glucose transport was inhibited by cytochalasin B; phloretin, phlorizin, and 1-fluoro-2,4-dinitrobenzene. D-glucose uptake was inhibited by 2-deoxy-D-glucose, 3-O-methyl-D-glucose and to a lesser extent by D-galactose. It was not inhibited by alpha-methyl-D-glucoside. Cytochalasin B binding to the vesicles was 30% inhibited in the presence of 80 mM D-glucose. The results indicate that the system for facilitated transport of D-glucose at the maternal face of the placenta is distinctly different from that on the brush-border membrane of intestine or renal tubule and more closely resembles that of human erythrocyte.

show abstract

Section: Discussionsupporting

confidence: 82%

Section: Discussionsupporting

confidence: 71%

mentioning

confidence: 99%

See 1 more Smart Citation

Glucose uptake into plasma membrane vesicles from the maternal surface of human placenta

et al. 1981

View full text Add to dashboard Cite

show abstract

“…This is probably due to a sharp fall in glucose supply resulting from urinary loss of glucose in the mother, and, to a lesser degree, in fetal urines. Furthermore, phloridzin could interfere with placental glucose transport since its aglycone, phloretin, decreases the transport of Z)-glucose in isolated guinea pig placenta (21) and in isolated human pla centa (5).…”

Section: Discussionmentioning

confidence: 99%

Fetal Metabolic Response to Phloridzin-Induced Hypoglycemia in Pregnant Rats

Freund¹,

Kervran²,

Assan³

et al. 1980

Neonatology

View full text Add to dashboard Cite

Phloridzin, an inhibitor of renal sugar transport, produces an important loss of glucose in urine of treated animals. In order to reduce severely the maternal glucose supply to the fetuses in short-term experiments, we have combined phloridzin administration to pregnant rats with 18 h starvation. Fetuses from starved phloridzin-treated mothers were compared with fetuses from starved mothers. Combined treatment markedly decreases fetal blood glucose concentration (––36%) and fetal liver glycogen stores (––76%). These changes are associated with a decrease in plasma insulin (––25%), a rise in plasma glucagon (+120%) and a marked increase of hepatic PEPCK activity (+400%). It appears from these results that phloridzin treatment for a short duration is able to induce glycogenolysis and the premature appearance of PEPCK in the liver of rat fetuses.

show abstract

“…1), which is not transported specifically in the hemochorial placenta [Schröder et al, 1975;Carstensen et al, 1977Carstensen et al, , 1983. Therefore the transport of Lalanine is largely stereospecifically in the guinea pig placenta.…”

Section: Discussionmentioning

confidence: 97%

<i>L</i>-Alanine Carriers at Maternal and Fetal Surfaces of the Guinea Pig Placenta Trophoblast

Carstensen

Leichtweiß²

1986

Gynecol Obstet Invest

View full text Add to dashboard Cite

An active transport for amino acids exists in maternofetal direction through the hemochorial placenta of man and guinea pig. With respect to the trophoblastic barrier some properties of the transplacental transport at both sides of this tissue are investigated. The results are compared to the methods of the transport of amino acids at intestine and kidney. The maternal and the fetal (basic) membrane can be investigated separately and one after another at one placenta by the technique of the bolus injections. The results were as follows: (1) The ³H-L-alanine uptake is significantly higher by maternal injection than by fetal injection. Opposite to this the backflux is higher out of the trophoblast into the perfusion medium of the donor side at fetal injections. Out of this transplacental transport is higher in maternofetal direction than in the opposite direction (p < 0.05). (2) A sodium dependence of the ³H-L-alanine transport is found at the maternal and fetal side. Nevertheless, the withdrawal of sodium ions inhibits more strongly at the maternal than at the fetal side. The sodium-dependent transport system predominates at the maternal membrane of the trophoblasts. (3) Phloretin only inhibits significantly the uptake (maximal) and the transport of ³H-L-alanine at the fetal side (at the basic membrane). That means that the sodium independent by phloretin inhibited transport system exists mostly, if not totally, at the fetal membrane. (4) Ouabain reduces uptake (maximal and total) and transport of ³H-L-alanine only significantly at the maternal side (p ≤ 0.05). Therefore the active sodium transport must be mostly localized at the maternal membrane. (5) The flux of L-alanine diminishes with increasing L-alanine concentrations at the fetal and maternal side. The determinations of the transport capacity (J_max) and the transport affinity (K_m) show that J_max is significantly higher at the maternal side and K_m at the fetal side (p ≤ 0.05). By means of these results a model can be described to characterise the transport of amino acid through the placenta.

show abstract

Evidence for a specific transport of D-hexoses across the human term placenta in vitro

Cited by 40 publications

References 10 publications

Glucose uptake into plasma membrane vesicles from the maternal surface of human placenta

Glucose uptake into plasma membrane vesicles from the maternal surface of human placenta

Fetal Metabolic Response to Phloridzin-Induced Hypoglycemia in Pregnant Rats

<i>L</i>-Alanine Carriers at Maternal and Fetal Surfaces of the Guinea Pig Placenta Trophoblast

Contact Info

Product

Resources

About