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Effect of insulin and dexamethasone on fetal assimilation of maternal glucose. Endocrinology 2011 Jan;152(1):255-62

Date

11/19/2010

Pubmed ID

21084442

Pubmed Central ID

PMC3219051

DOI

10.1210/en.2010-0959

Scopus ID

2-s2.0-78650847598   11 Citations

Abstract

The growing fetus depends upon transfer of glucose from maternal blood to fetal tissues. Insulin and glucocorticoid impact maternal glucose metabolism, but the effects of these hormones on fetal glucose assimilation in vivo are understudied. We thus used positron emission tomography imaging to determine the disposition of [(18)F]fluorodeoxyglucose (FDG) in rats on gestational d 20, quantifying the kinetic competition of maternal tissues and fetus for glucose. Three fasting maternal states were studied: after 2-d dexamethasone (DEX), during euglycemic hyperinsulinemic clamp insulin receiving (INS), and control (CON). In CON and DEX mothers, FDG accumulation in fetuses and placentae was substantial, rivaling that of maternal brain. By contrast, FDG accumulation was reduced in INS fetuses, placentae, and maternal brain by approximately 2-fold, despite no diminution in FDG extraction kinetics from maternal blood into these structures. The reduced FDG accumulation was due to more rapid clearance of FDG from the circulation in INS mothers, related to increased FDG avidity in INS select maternal tissues, including skeletal muscle, brown adipose tissue, and heart. DEX treatment of mothers reduced fetal weight by nearly 10%. Nonetheless, the accumulation of FDG into placentae and fetuses was similar in DEX and CON mothers. In our rat model, fetal growth restriction induced by DEX does not involve diminished glucose transport to the fetus. Maternal insulin action has little effect on the inherent avidity of the fetal-placental unit for glucose but increases glucose utilization by maternal tissues, thus indirectly reducing the glucose available to the fetus.

Author List

Norris AW, Wang C, Yao J, Walsh SA, Sawatzke AB, Hu S, Sunderland JJ, Segar JL, Ponto LL

Author

Jeffrey L. Segar MD Professor in the Pediatrics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Dexamethasone
Female
Fetus
Glucose
Insulin
Maternal-Fetal Exchange
Positron-Emission Tomography
Pregnancy
Rats
Rats, Sprague-Dawley
jenkins-FCD Prod-486 e3098984f26de787f5ecab75090d0a28e7f4f7c0