Estriol

Climacteric : the journal of the International Menopause Society · 2024

Researchers found that using vaginal estriol (E3) does not significantly change levels of key hormones in the blood of postmenopausal women. While some studies noted minor and temporary changes in certain hormone levels, these remained within safe ranges. Overall, the findings support the safety of vaginal E3 for treating menopause-related symptoms.

• No significant changes in serum estrone, estradiol, testosterone, progesterone, and sex hormone binding globulin levels after using vaginal E3.
• Minimal and transient decreases in serum gonadotropin levels were observed, but they stayed within postmenopausal ranges.
• A few studies reported slight increases in serum E3 levels, but most showed no changes.

JCI insight · 2023

Researchers found that different natural estrogens, particularly 17β-estradiol (E2), estriol (E3), and estetrol (E4), promote healing in blood vessels after injury. While E2 and E3 were effective in healing damaged endothelial cells, E4 showed a unique action that relies on interactions with smooth muscle cells rather than the typical pathways used by E2. This highlights the distinct roles of these estrogens in vascular health.

• E2, E3, and E4 equally stimulated reendothelialization after certain injuries.
• E2 and E3 accelerated healing after more severe injuries, while E4's action depended on smooth muscle cells.
• E4 operates through different mechanisms than E2, indicating its unique role in vascular protection.

Climacteric : the journal of the International Menopause Society · 2018

Researchers observed that a combination of ultra-low dose estriol and Lactobacillus acidophilus can effectively treat vaginal atrophy in menopausal women. This therapy improves symptoms and quality of life while being well tolerated and having minimal side effects.

• The combination supports vaginal health by promoting tissue growth and restoring healthy bacteria.
• It has a low incidence of side effects and negligible absorption of estriol.
• Recent guidelines recommend this therapy as a viable option for treating vaginal atrophy.

The Australian & New Zealand journal of obstetrics & gynaecology · 1991

Researchers observed that low levels of oestriol in urine during pregnancy were linked to higher risks of stillbirth, neonatal death, and fetal growth issues. They noted improvements in perinatal outcomes over time, but low oestriol levels still indicated significant risks. Additionally, treatment with intravenous nutrients helped improve outcomes for some patients with persistently low oestriol levels.

• 10.7% of patients had low oestriol values, leading to much higher stillbirth and neonatal death rates.
• Perinatal mortality rates improved from 1971-1984 to 1985-1989, but low oestriol levels still posed significant risks.
• Intravenous nutrient treatment improved outcomes for some patients with low oestriol values.

Cancer detection and prevention · 1987

Researchers observed a connection between dietary fat intake and breast cancer risk, influenced by factors like location and economic status. They reviewed how certain types of fats, particularly trans fats, may interact with hormones related to breast cancer development.

• Dietary habits can affect breast cancer incidence.
• Trans-fatty acids may play a role in breast cancer risk.
• Hormones like estrone and estradiol are linked to dietary fat intake.

Journal of steroid biochemistry · 1984

Researchers observed that estriol, the main estrogen during pregnancy, is produced in the placenta and enters the mother's bloodstream, where it is transformed into various forms. They found that some forms of estriol are cleared from the body more quickly than others, and after childbirth, the levels of estriol drop rapidly, while its other forms decrease more slowly.

• Estriol is mainly produced in the placenta from fetal precursors.
• Estriol is converted into several different forms in the mother's body.
• After delivery, estriol levels drop quickly, while its conjugates decline more slowly.

Maturitas · 1982

Researchers observed that oestriol can produce strong estrogen effects if maintained at high levels in target tissues through frequent administration. They found that oestriol acts quickly but does not last long in the body, meaning its effects depend on how and how often it is given.

• Oestriol's potency varies based on testing conditions.
• High levels of oestriol are needed for full estrogen effects.
• Oestriol is short-acting, requiring frequent dosing for effectiveness.

Acta endocrinologica · 1982

Researchers found that oestriol is quickly absorbed into the bloodstream after oral administration, with levels peaking around 45 minutes later. However, these levels drop back to low amounts within a few hours, suggesting that oestriol is rapidly metabolized and has a short duration of effect.

• Oestriol levels in post-menopausal women are generally very low.
• Plasma oestriol levels rise shortly after taking it orally.
• The short duration of elevated oestriol may explain its weak effects as an estrogen.

The Journal of clinical investigation · 1968

Researchers found that patients with cirrhosis have abnormal metabolism of estrogen compared to healthy individuals. They observed increased levels of certain estrogen metabolites and decreased levels of others, suggesting a disruption in how the body processes these hormones. This research helps explain the higher estrogen levels often seen in cirrhosis patients.

• Patients with cirrhosis excreted more total estrogen metabolites in urine compared to healthy controls.
• There was a significant decrease in the excretion of 2-hydroxyestrone and 2-methoxyestrone in cirrhosis patients.
• Cirrhosis was associated with an increase in 16alpha-hydroxyestrone, indicating a specific hormonal imbalance.