What question did this study set out to answer?

This study investigates how placenta-specific GLUT4 knockout alters offspring metabolism under dietary stress.

May 14, 2026

Improved glucose tolerance in high-fat diet challenged male offspring of placental glut4 hetero- and homozygous knockout in mice

Key Points

This study investigates how placenta-specific GLUT4 knockout alters offspring metabolism under dietary stress.
Transgenic Tpbpa-cre mice crossed to GLUT4 floxed carriers created offspring with different GLUT4 genotypes.
Timed pregnancies set up to collect placentas and embryos at embryonic day 17.5 (E17.5).
Offspring underwent intraperitoneal glucose tolerance tests and insulin tolerance tests on normal chow or high-fat diets.
No differences in placental sufficiency among Ctrl, Hets, or KO offspring.
Male offspring on a normal diet showed no differences in glucose tolerance or insulin sensitivity.
At 14 weeks post-high-fat diet, Het and KO males demonstrated improved glucose tolerance compared to others.

Abstract

Background: The placenta is an essential organ for nutrient transport between the maternal-fetal interface to support fetal growth. The in-utero environment is influenced by maternal health; for example, maternal obesity or hyperinsulinemia alters nutrient transporter expression and consequently predisposes the offspring to metabolic dysfunction later in life. Glucose transporters (GLUT) 1 and 3 are highly expressed in the placenta, but the contribution of insulin-dependent GLUT4 to placental physiology in late pregnancy and its effect on fetal metabolic programming remain unknown. The study objective is to understand how the placental junctional zone GLUT4 affects placental and fetal physiology. We hypothesize that knocking out GLUT4 in placental endocrine cells will lead to placental insufficiency, causing metabolic dysfunction in offspring later in life, especially under metabolic challenges such as a high-fat diet (HFD). Methods: To test this hypothesis, transgenic Tpbpa-cre mice were crossed to GLUT4 floxed carriers to generate littermate controls (Ctrl), Tpbpa-cre; GLUT4 f/+ (Hets), or Tpbpa-cre; GLUT4 f/f (KO) offspring. In embryonic studies, timed pregnancies were set up, and at embryonic day 17.5 of gestation (E17.5), the pregnant dams were sacrificed, and the placenta and embryos were collected. In fetal programming studies, normal chow diet-fed (NCD) or HFD-fed offspring underwent in vivo metabolic testing, including intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT). Data: There were no differences in placental sufficiency between Ctrl, Hets, or KO offspring placenta or in embryonic weight across genotype. Male offspring on NCD did not display any differences in glucose tolerance or insulin sensitivity. Under HFD, male offspring did not have any difference in 2 or 4 weeks IPGTT nor changes in ITT at 8 weeks HFD. However, at 14 weeks post-HFD, Het and KO male offspring displayed improved glucose tolerance. Summary of results: No difference in placental sufficiency, but Hets and KO males at 14 weeks HFD show glucose tolerance protection from metabolic challenge. Conclusion: These results indicate that placental GLUT4 Het or KO males may be protected from HFD challenge, implicating a role of GLUT4 in fetal programming of metabolic dysfunction. Limitations: These studies were only performed in male mice. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

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