Maternal-fetal transport kinetics of L-Leucine in vitro in gestational diabetic pregnancies.
OBJECTIVE
Paucity of data relating to transport of amino acids in gestational diabetic pregnancies prompted us to undertake this study. Transport kinetics of a model amino acid, L-leucine was investigated in gestational diabetic pregnancies in vitro, using perfusion of isolated placental lobules.


METHODS
Placentae from diabetic and control pregnant women were collected post-partum. Suitable placental lobules were then perfused, using National Culture and Tissue Collection (NCTC) medium, diluted with Earle's buffered salt solution as perfusate. 14C-labelled L-leucine along with tritiated water as reference were injected as a 100 ul bolus into the maternal circulation and serial perfusate samples collected over a 5-minute study period.


RESULTS
In 6 successful perfusions, differential transport rate of L-leucine for 10, 25, 50, 75 and 90% of efflux in the fetal vein averaged 1.17, 1.12, 1.22, 1.20 and 1.17 times respectively that of reference in the diabetic group. In the control group (n=6), leucine transport indices for the corresponding efflux periods averaged 1.13, 1.15, 1.18, 1.17 and 1.16 times respectively that of the reference marker. Student's 't' test showed that the difference between the two groups was not statistically significant (p > 0.05) for all the efflux fractions studied. In the diabetic series, leucine transport fraction (TF) averaged 41.2 +/- 4.5% of corresponding water TF while in control group, the amino acid TF averaged 46.5 +/- 6.5% of water TF. The difference between the two series, however was not statistically significant (p > 0.05). Similarly, kinetic parameters as area under the curve, clearance, elimination constant, time for maximum response, absorption rate, and elimination rate in the diabetic and control groups, were not significantly different (p > 0.05) as well.


CONCLUSIONS
Our study seems to indicate that transport kinetics of leucine under in vitro conditions, do not differ significantly in placentae of gestational diabetic women compared to controls.
Nandakumaran
M
M
Obstetrics and Gynecology Department, Faculty of Medicine, University of Kuwait, Safat. moorkath@hsc.kuniv.edu.kw
Al-Shammari
M
M
Al-Saleh
E
E
D000328:Adult; D001692:Biological Transport; D001724:Birth Weight; D001835:Body Weight; D016640:Diabetes, Gestational / Q000097:blood*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D007930:Leucine / Q000097:blood / Q000378:metabolism*; D008431:Maternal-Fetal Exchange / Q000502:physiology*; D011247:Pregnancy; D012016:Reference Values; D015430:Weight Gain
D007930:Leucine