Effect of hyperglycaemic load on maternal-foetal transport of L-leucine in perfused human placental lobule: in vitro study.
The effect of hyperglycaemic loads on L-leucine transport in the maternal-foetal direction has been investigated in human placenta in vitro, using perfusion of isolated placental lobules. National Culture and Tissue Collection medium diluted with Earle's buffered salt solution was used as the perfusate. (14)C-labelled L-leucine along with tritiated water as reference were injected as a 100-microl bolus into the maternal circulation and serial perfusate samples were collected over a 5-min study period. In 6 successful perfusions, the differential transport rate of leucine for 10, 25, 50, 75 and 90% of efflux in the foetal vein averaged 1.26, 1.10, 1.19, 1.10 and 1.04 times respectively that of reference in the control euglycaemic phase. In the experimental hyperglycaemic phases of 27.8 and 55.6 mM/l, leucine transport for the corresponding efflux periods averaged 1.37, 1.33, 1.28, 1.22 and 1.26 times and 1.16, 0.97, 1.08, 1.08 and 1.08 times respectively that of the reference marker. Analysis of variance (ANOVA) test showed that the difference between the three groups was not statistically significant. In the control euglycaemic phase, leucine transport fraction (TF) averaged 40.90+/-3.51% of corresponding water TF while in experimental hyperglycaemic phases, TF of the amino acid averaged 37.80+/-4.82% and 35.61+/-3.21% of water TF respectively. The difference between the control and hyperglycaemic perfusion phases was not statistically significant. Further, no statistical difference could be shown between the two hyperglycaemic perfusion series themselves. Similarly, kinetic parameters such as absorption rate, elimination rate and absorption rate:elimination rate ratio were not significantly different in the hyperglycaemic perfusion phases compared to control phase. Our studies seem to indicate that leucine transport kinetics in in vitro conditions are not altered significantly in placentas exposed to hyperglycaemic loads.
Nandakumaran
M
M
Obstetrics and Gynecology Department, Faculty of Medicine, University of Kuwait, 24923, Safat 13110, Kuwait. moorkath@hsc.kuniv.edu.kw
Al-Saleh
E
E
Al-Shammari
M
M
Harouny
A K
AK
D019540:Area Under Curve; D001692:Biological Transport; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000493:pharmacokinetics*; D008431:Maternal-Fetal Exchange / Q000502:physiology*; D010477:Perfusion; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000378:metabolism; D046509:Tissue Culture Techniques
D007930:Leucine