Bidirectional placental transfer ('leak') of L-glucose in control and diabetic rats.
The placental transfer of D- and L-glucose was investigated in anaesthetised non-diabetic and streptozotocin-induced diabetic rats. Maternal to fetal transfer was determined by perfusing the fetal side of one placenta in situ whilst infusing a mixture of D-[3-3H]glucose and L-[1-14C]glucose into the maternal circulation. Back-transfer from the fetal to maternal circulation was assessed by determining the uptake of the radiolabelled glucoses from the perfusion fluid during a single passage through the placenta on the fetal side. Maternal diabetes resulted in a reduced utero-placental blood flow but an increased bidirectional transfer of D-glucose. Non-specific maternal to fetal placental transfer of L-glucose was greater in diabetic rats than in controls, and the loss of L-glucose during placental perfusion on the fetal side was, again, greater in diabetic than in control rats. This increased bidirectional 'leak' of glucose possibly reflects a functionally compromised placenta, caused by its formation in a diabetic milieu, and may explain the greater fetal-maternal glucose ratios found in diabetic rats relative to controls.
Thomas
C R
CR
Division of Medicine, United Medical School of Guy's Hospital, London, UK.
Lowy
C
C
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002250:Carbon Radioisotopes; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005260:Female; D005312:Fetal Blood; D005333:Fetus / Q000502:physiology; D005947:Glucose / Q000378:metabolism*; D008297:Male; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000378:metabolism*; D011270:Pregnancy, Animal / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D051381:Rats; D012016:Reference Values; D013237:Stereoisomerism; D014316:Tritium
D001786:Blood Glucose; D002250:Carbon Radioisotopes; D014316:Tritium; D005947:Glucose