Metabolic pathways for glucose and fructose : I synthesis and metabolism of fructose by ovine conceptuses

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Fructose, the most abundant hexose sugar in fetal fluids and blood of sheep and other ungulates and cetaceans, is synthesized from glucose via the polyol pathway in trophectoderm and chorion. However, the cell-specific and temporal expression of enzymes for the synthesis and metabolism of fructose in sheep conceptuses (embryo and placental membranes) and placentomes has not been characterized. This study characterized key enzymes involved in fructose synthesis and metabolism by ovine conceptuses throughout pregnancy. Day 17 conceptuses expressed mRNAs for the polyol pathway (SORD and AKR1B1) and glucose and fructose metabolism (HK1, HK2, G6PD, OGT, and FBP), but not those required for gluconeogenesis (G6Pase or PCK). Ovine placentomes also expressed mRNAs for SORD, AKR1B1, HK1, and OGT. Fructose can be metabolized via the ketohexokinase (KHK) pathway and isoforms, KHK-A and KHK-C, were expressed in ovine conceptuses from Day 16 of pregnancy and placentomes during pregnancy in a cell specific manner: KHK-A protein was more abundant in trophectoderm and cotyledons of placentomes, while KHK-C protein was more abundant in endoderm of Day 16 conceptuses and chorionic epithelium in placentomes. Expression of KHK mRNAs in placentomes was greatest at Day 30 of pregnancy (P < 0.05), but not different among days later in gestation. These results provide novel insights into the synthesis and metabolism of fructose via the uninhibited KHK pathway in ovine conceptuses to generate ATP via the TCA cycle, as well as substrates for the pentose cycle, hexosamine biosynthesis pathway and one-carbon metabolism required for conceptus development throughout pregnancy.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - year:2024

Enthalten in:

Biology of reproduction - (2024) vom: 19. März

Sprache:

Englisch

Beteiligte Personen:

Moses, Robyn M [VerfasserIn]
Stenhouse, Claire [VerfasserIn]
Halloran, Katherine M [VerfasserIn]
Sah, Nirvay [VerfasserIn]
Hoskins, Emily C [VerfasserIn]
Washburn, Shannon E [VerfasserIn]
Johnson, Gregory A [VerfasserIn]
Wu, Guoyao [VerfasserIn]
Bazer, Fuller W [VerfasserIn]

Links:

Volltext

Themen:

Conceptus
Fructose
Glucose
Journal Article
Metabolism
Ovine
Placentome
Pregnancy
Uterus

Anmerkungen:

Date Revised 19.03.2024

published: Print-Electronic

Citation Status Publisher

doi:

10.1093/biolre/ioae043

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM36991483X