Research · PMID 19038856 · Landmark study
Reviewed by Neal Rouzier, MD, Preventive Medicine · Sep 2026
Select nutrients in the ovine uterine lumen. III. Cationic amino acid transporters in the ovine uterus and peri-implantation conceptuses.
Biology of reproduction · March 2009 · Haijun Gao, Guoyao Wu, Thomas E Spencer, Gregory A Johnson, Fuller W Bazer
What this study found
Arginine is an essential amino acid for conceptus (embryo/fetus and trophoblast/placenta) growth and development; however, the mechanisms for arginine transport into the uterine lumen and uptake by conceptuses are largely unknown. In this study, expression of System y(+) (SLC7A1, SLC7A2, and SLC7A3) cationic amino acid transporters in uteri of cyclic and pregnant ewes and conceptuses was studied, and effects of pregnancy, progesterone (P4), and interferon tau (IFNT) on their expression were investigated.
Why this trial matters
Transdermal estrogen VTE
How RAGMD uses this study
Clinical questions this paper informs
Synthesis lives on the evidence question — this page shows where the study sits in that analysis.
Supporting literature
Does hormone replacement therapy increase venous thromboembolism risk?
Oral estrogen increases venous thromboembolism risk compared with no therapy. Transdermal estrogen appears to carry lower thrombotic risk in observational studies and is often preferred in women at elevated VTE risk.
Open evidence analysisSupporting literature
Is transdermal estrogen preferred over oral estrogen in menopause?
Transdermal estrogen avoids first-pass hepatic effects and is associated with lower venous thromboembolism risk than oral routes in observational data. It is often preferred in women with elevated thrombotic or metabolic risk.
Open evidence analysis