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Influence of cations on basic and neutral amino acid uptake by human placental villi
Abstracts: I.M. W.P.A. Austruliu 1994
EFFECTS OF EXTRACELLULAR MATRIX PROTEINS UPON PROLIFERATION OF ECTOPLACENTAL CONE CELLS OF THE MOUSE BLASTOCYST CULTURED IN VITRO. H. Koi’, Y. Shimlzu’, S. Sakamoto’, C. Tachi’ and T. Aso’, Department of Obstetrics and Gynecology I, School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan. Laboratory of Applied Genetic9, Department of Animal Resource Sciences, Graduate School of Agriculture, University of Tokyo, Tokyo, Japan. As an attempt to understand the mechanisms underlying the trophoblastic invasion, we investigated effects of fetal bovine serum (FBS) and the matrix substratum upon the trophoblastic giant cells (TGCs) and ectoplacental cone cells (EPC cells) of the mouse blastocysts. The blastocysts were IVFproduced and cultured in modified Eagle’s minimum essential medium fortified with FBS or serum components divided by affinity chromatography on the glass substratum coated or non-coated with matrix proteins. The results demonstrated that 1) non heparin-binding substances in FBS induced the spreading of the TGCs more promptly than heparin-binding substances in FBS, 2) the latter substances were essential for the continuous spreading of the TGCs, 3) tibronectin, lamlnin, type I collagen and type IV collagen substratum had little influence upon the primary spreading of TGCs induced by non heparin-binding substances in FBS, 4) fibronectin substratum promoted the remarkable proliferation of EPC cells but laminin did rarely and type I and IV collagen didn’t, Our results strongly indicate that the interaction of EPC cells with the fibronectin substratum is a prerequisite for the induction of prominent cell proliferation of the EPC of mouse blastocysts in vitro, and possibly the formation of the definitive placentae in vivo as well in this species.
INFLUENCE OF CATIONS ON BASIC AND NEUTRAL AMINO ACID UPTAKE BY HUMAN PLACENTAL VILLL Roy. B. Krishna, Joseph Dancis and Mortimer Levitz. Departments of Obstetrics and Gynecology and Pediatrics. New York University Medical Center. New York. USA. Sodium dependency and the irdbtence of cations on alanine, lysine, arginine and leucine uptake in human placental villi were investigated. Uptake was expressed as the mean distribution ratio of the intracellular to extracellular concentrations f SD., after 30 min incubations. In NaCl buffer, alanine uptake was 2.50i0.41 (n=6) and in choline bufFer it was &premed to 1.45fo.20 (n=6, pcO.001) indicating Na+-dependency. By contrast, lysine uptake from NaCl buffer was 1.34ti.33 (n=l7), increasing to 3.97fo.65 (ne16) in choline buffer. The quaternary amines, tetraethylammonium (TEA) and ace@-@WhylcboIIne also increased Iysine uptake. The tertiary amine, hordenine had a lesser et&cl whereas the secondary amine, ephedrine had no effect. Arginine behaved like lysine except that uptake was unaffected by bordenine and ephedrine depressed uptake. The choline e&t was manircsted only at high concentrations (> 100 mM). TEA had a small but significant effect at low concentrations (12-3OmM) and an e&t comparable to choline at concentrations > 1OOmM.The rate of efIIux of lysine accumulated by placental villi in choline bu.lTer was considerably slower than that accumulated from NaCl buftbr and the composition of the efnux buffer medium did not affect the rate ofrelease. The uptake ofthe neutral Na+-independent amino acid, leucine was unaffected by choline or TEA in the buffer. The data indicate that quaternary amines in hi concentrations dramatically promote uptake of basic amino eh acids, possibly by activating the Na -independent y+ transporter. The modest uptake of lysineat low concentrations of TEA suggests a second stimulatory mechanism, perhaps related to K+ channel influence on intracellular Ca” in placental villi.
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EFFECTS OF EXTRACELLULAR MATRIX PROTEINS UPON PROLIFERATION OF ECTOPLACENTAL CONE CELLS OF THE MOUSE BLASTOCYST CULTURED IN VITRO. H. Koi’, Y. Shimlzu’, S. Sakamoto’, C. Tachi’ and T. Aso’, Department of Obstetrics and Gynecology I, School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan. Laboratory of Applied Genetic9, Department of Animal Resource Sciences, Graduate School of Agriculture, University of Tokyo, Tokyo, Japan. As an attempt to understand the mechanisms underlying the trophoblastic invasion, we investigated effects of fetal bovine serum (FBS) and the matrix substratum upon the trophoblastic giant cells (TGCs) and ectoplacental cone cells (EPC cells) of the mouse blastocysts. The blastocysts were IVFproduced and cultured in modified Eagle’s minimum essential medium fortified with FBS or serum components divided by affinity chromatography on the glass substratum coated or non-coated with matrix proteins. The results demonstrated that 1) non heparin-binding substances in FBS induced the spreading of the TGCs more promptly than heparin-binding substances in FBS, 2) the latter substances were essential for the continuous spreading of the TGCs, 3) tibronectin, lamlnin, type I collagen and type IV collagen substratum had little influence upon the primary spreading of TGCs induced by non heparin-binding substances in FBS, 4) fibronectin substratum promoted the remarkable proliferation of EPC cells but laminin did rarely and type I and IV collagen didn’t, Our results strongly indicate that the interaction of EPC cells with the fibronectin substratum is a prerequisite for the induction of prominent cell proliferation of the EPC of mouse blastocysts in vitro, and possibly the formation of the definitive placentae in vivo as well in this species.
INFLUENCE OF CATIONS ON BASIC AND NEUTRAL AMINO ACID UPTAKE BY HUMAN PLACENTAL VILLL Roy. B. Krishna, Joseph Dancis and Mortimer Levitz. Departments of Obstetrics and Gynecology and Pediatrics. New York University Medical Center. New York. USA. Sodium dependency and the irdbtence of cations on alanine, lysine, arginine and leucine uptake in human placental villi were investigated. Uptake was expressed as the mean distribution ratio of the intracellular to extracellular concentrations f SD., after 30 min incubations. In NaCl buffer, alanine uptake was 2.50i0.41 (n=6) and in choline bufFer it was &premed to 1.45fo.20 (n=6, pcO.001) indicating Na+-dependency. By contrast, lysine uptake from NaCl buffer was 1.34ti.33 (n=l7), increasing to 3.97fo.65 (ne16) in choline buffer. The quaternary amines, tetraethylammonium (TEA) and ace@-@WhylcboIIne also increased Iysine uptake. The tertiary amine, hordenine had a lesser et&cl whereas the secondary amine, ephedrine had no effect. Arginine behaved like lysine except that uptake was unaffected by bordenine and ephedrine depressed uptake. The choline e&t was manircsted only at high concentrations (> 100 mM). TEA had a small but significant effect at low concentrations (12-3OmM) and an e&t comparable to choline at concentrations > 1OOmM.The rate of efIIux of lysine accumulated by placental villi in choline bu.lTer was considerably slower than that accumulated from NaCl buftbr and the composition of the efnux buffer medium did not affect the rate ofrelease. The uptake ofthe neutral Na+-independent amino acid, leucine was unaffected by choline or TEA in the buffer. The data indicate that quaternary amines in hi concentrations dramatically promote uptake of basic amino eh acids, possibly by activating the Na -independent y+ transporter. The modest uptake of lysineat low concentrations of TEA suggests a second stimulatory mechanism, perhaps related to K+ channel influence on intracellular Ca” in placental villi.
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