What factors determine placental glucose transfer kinetics?☆

نویسندگان

  • P.E. Day
  • J.K. Cleal
  • E.M. Lofthouse
  • M.A. Hanson
  • R.M. Lewis
چکیده

INTRODUCTION Transfer of glucose across the human placenta is directly proportional to maternal glucose concentrations even when these are well above the physiological range. This study investigates the relationship between maternal and fetal glucose concentrations and transfer across the placenta. METHODS Transfer of d-glucose, (3)H-3-o-methyl-d-glucose ((3)H-3MG) and (14)C-l-glucose across the isolated perfused human placental cotyledon was determined for maternal and fetal arterial d-glucose concentrations between 0 and 20 mmol/l. RESULTS Clearance of (3)H-3MG or (14)C-l-glucose was not affected by maternal or fetal d-glucose concentrations in either circulation. DISCUSSION Based on the arterial glucose concentrations and the reported KM for GLUT1, the transfer of d-glucose and (3)H-3MG would be expected to show signs of saturation as d-glucose concentrations increased but this did not occur. One explanation for this is that incomplete mixing of maternal blood and the rate of diffusion across unstirred layers may lower the effective concentration of glucose at the microvillous membrane and subsequently at the basal membrane. Uncertainties about the affinity of GLUT1 for glucose, both outside and inside the cell, may also contribute to the difference between the predicted and observed kinetics. CONCLUSION These factors may therefore help explain why the observed and predicted kinetics differ and they emphasise the importance of understanding the function of transport proteins in their physiological context. The development of a computational model of glucose transfer may improve our understanding of how the determinants of placental glucose transfer interact and function as a system.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Maternal undernutrition during mid-pregnancy in sheep. Placental size and its relationship to calcium transfer during late pregnancy.

The aim of the present experiment was to determine the relationship between placental and fetal weight after placental growth had been retarded by maternal undernutrition. Placental weight and fetal weight were measured in single-lamb-bearing ewes which were well-fed throughout pregnancy, or severely undernourished between the 30th and 96th day of pregnancy. Placental transfer of calcium and wh...

متن کامل

Factors affecting the response to insulin in the normal subhuman pregnant primate.

The concentrations of plasma glucose, free fatty acids, insulin, growth hormone, and placental prolactin in subhuman primate fetal and maternal plasma were examined following intravascular administration of insulin and glucagon to the fetus and mother. The neonatal plasma responses to these same stimuli were also examined. Fetal plasma glucose concentrations were minimally altered by direct fet...

متن کامل

Mechanisms Involved in the Placental Glucose Transfer

The mechanisms involved in both placental uptake and transfer of macronutrients are reviewed. Fatty acid, cholesterol and amino acid transport across the placenta involves a complex system to ensure nutrient delivery to the growing fetus. The placental glucose transfer is important for fetal macrosomia, but lipid disturbances in both maternal and placental compartments may contribute to neonata...

متن کامل

Placental Nutrient Transport in Gestational Diabetic Pregnancies

Maternal obesity during pregnancy is rising and is associated with increased risk of developing gestational diabetes mellitus (GDM), defined as glucose intolerance first diagnosed in pregnancy (1). Fetal growth is determined by the maternal nutrient supply and placental nutrient transfer capacity. GDM-complicated pregnancies are more likely to be complicated by fetal overgrowth or excess adipos...

متن کامل

Regulation of placental nutrient transport and implications for fetal growth.

Fetal macronutrient requirements for oxidative metabolism and growth are met by placental transport of glucose, amino acids, and, to a lesser extent that varies with species, fatty acids. It is becoming possible to relate the maternal-fetal transport kinetics of these molecules in vivo to the expression and distribution of specific transporters among placental cell types and subcellular membran...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 34  شماره 

صفحات  -

تاریخ انتشار 2013