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Developmental changes in nitric oxide synthesis in the ovine placenta
Hyukjung Kwon1, Guoyao Wu, Cynthia J Meininger
1Department of Animal Science and Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, Texas 77843-2471, USA.
Biology of Reproduction
|November 14, 2003
Summary
Nitric oxide (NO) synthesis in sheep placenta is highest in early gestation, peaking around Day 60. This NO production is metabolically coordinated with essential cofactors and enzymes, crucial for conceptus and uterine development.
Area of Science:
- Reproductive Biology
- Physiology
- Biochemistry
Background:
- Nitric oxide (NO) is vital for placental growth and angiogenesis.
- Limited information exists on NO synthesis during ovine conceptus development.
Purpose of the Study:
- To investigate placental NO synthesis throughout ovine gestation.
- To test the hypothesis that NO synthesis is greatest in early gestation.
Main Methods:
- Ovine placental and endometrial tissues were collected from Days 30 to 140 of gestation.
- Assays included NO synthesis, nitric oxide synthase (NOS) activities (cNOS, iNOS), and cofactor concentrations (BH4, NADPH).
- GTP-cyclohydrolase I (GTP-CH) activity was also measured.
Main Results:
- NO synthesis peaked around Day 60 in placentomes and intercotyledonary placenta, and Days 40-60 in endometrium.
- Significant changes in NO synthesis, NOS activities, and cofactor levels were observed across gestation.
- NO synthesis correlated positively with total NOS activity, GTP-CH activity, BH4, and NADPH concentrations.
Conclusions:
- Placental NO synthesis is highest in early to mid-gestation in sheep.
- Metabolic pathways supporting NO synthesis are highly coordinated.
- These findings provide a foundation for understanding NO's role in ovine fetal-placental development.