L-[1-13C]Leucine, [1-13C]glycine, L-[1-13C]phenylalanine, and L-[1-13C]proline were infused as a bolus into the maternal circulation of seven appropriate for gestational age at 30.3 ± 3.0 wk and 7 intrauterine growth-restricted pregnancies at 26.5 ± 1.0 wk gestation to investigate placental transport in vivo. Umbilical venous samples were obtained at the time of in utero fetal blood sampling at 450 ± 74 sec from the bolus injection. In normal pregnancies the fetal/maternal (F/M) enrichment ratios for leucine (0.76 ± 0.06) and phenylalanine (0.77 ± 0.06) were higher (P < 0.01) than the F/M ratios for glycine (0.18 ± 0.04) and proline (0.22 ± 0.02). This suggests that these two essential amino acids rapidly cross the placenta in vivo. Compared with the essentials, both glycine and proline had significantly lower F/M enrichment ratios, which were not different from each other. The results support the hypothesis that amino acids with high affinity for exchange transporters cross the placenta most rapidly. In intrauterine growth-restricted pregnancies, the F/M enrichment ratio was significantly lower (P < 0.01) for L-[1-13C]leucine (0.76 ± 0.06 vs. 0.48 ± 0.07) and for L-[1-13C]phenylalanine (0.77 ± 0.06 vs. 0.46 ± 0.07) compared with appropriate for gestational age pregnancies reflecting impaired transplacental flux. The F/M enrichment ratio did not differ for [1-13C]glycine (0.18 ± 0.04 vs. 0.17 ± 0.03), and L-[1-13C]proline (0.22 ± 0.02 vs. 0.18 ± 0.04).

Placental transport of leucine, phenylalanine, glycine and proline in intrauterine growth-restricted pregnancies / C.L. Paolini, A.M. Marconi, S. Ronzoni, M. Di Noio, P.V. Fennessey, G. Pardi, F.C. Battaglia. - In: THE JOURNAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM. - ISSN 0021-972X. - 86:11(2001), pp. 5427-5432. [10.1210/jc.86.11.5427]

Placental transport of leucine, phenylalanine, glycine and proline in intrauterine growth-restricted pregnancies

C.L. Paolini
Primo
;
A.M. Marconi
Secondo
;
M. DI NOIO;G. Pardi
Penultimo
;
2001

Abstract

L-[1-13C]Leucine, [1-13C]glycine, L-[1-13C]phenylalanine, and L-[1-13C]proline were infused as a bolus into the maternal circulation of seven appropriate for gestational age at 30.3 ± 3.0 wk and 7 intrauterine growth-restricted pregnancies at 26.5 ± 1.0 wk gestation to investigate placental transport in vivo. Umbilical venous samples were obtained at the time of in utero fetal blood sampling at 450 ± 74 sec from the bolus injection. In normal pregnancies the fetal/maternal (F/M) enrichment ratios for leucine (0.76 ± 0.06) and phenylalanine (0.77 ± 0.06) were higher (P < 0.01) than the F/M ratios for glycine (0.18 ± 0.04) and proline (0.22 ± 0.02). This suggests that these two essential amino acids rapidly cross the placenta in vivo. Compared with the essentials, both glycine and proline had significantly lower F/M enrichment ratios, which were not different from each other. The results support the hypothesis that amino acids with high affinity for exchange transporters cross the placenta most rapidly. In intrauterine growth-restricted pregnancies, the F/M enrichment ratio was significantly lower (P < 0.01) for L-[1-13C]leucine (0.76 ± 0.06 vs. 0.48 ± 0.07) and for L-[1-13C]phenylalanine (0.77 ± 0.06 vs. 0.46 ± 0.07) compared with appropriate for gestational age pregnancies reflecting impaired transplacental flux. The F/M enrichment ratio did not differ for [1-13C]glycine (0.18 ± 0.04 vs. 0.17 ± 0.03), and L-[1-13C]proline (0.22 ± 0.02 vs. 0.18 ± 0.04).
Settore MED/40 - Ginecologia e Ostetricia
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/33207
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