Estriol

Toxicity

ORAL (LD50): Acute: >2000 mg/kg [Rat].

Description

Estriol is significantly less active than estradiol; however, it has a selective ability to stimulate blood flow and restoration of genital epithelium. In addition, using this drug reduces mental symptoms of menopausal syndrome. It is used in the premenopausal and menopausal periods, for skin atrophy and signs of genital degeneration, and so on.

Description

Estriol is a metabolite of estradiol and a major estrogen produced in the later stages of pregnancy. In a longitudinal study in healthy pregnant women, total plasma estriol levels increased from <10 ng/ml at 8-10 weeks gestation to approximately 150 ng/ml at week 38. The majority of the estriol synthesized in the later stages of pregnancy originates from fetal dehydroepiandrosterone sulfate (DHEAS) and serves as a direct marker of fetal adrenal gland activity. Saliva contains primarily unbound and unconjugated estriol and is commonly used for monitoring estriol levels. Plasma levels of estriol in males and non-pregnant females is less than 2 ng/ml.

Chemical properties

White or almost white, crystalline powder.

The Uses of Estriol

A metabolite of Estradiol. An estrogenic metabolite considerably less potent than the hormone Estradiol

The Uses of Estriol

17b-estradiol metabolite, primary estrogen in urine

The Uses of Estriol

A metabolite of Estradiol (E888000). An estrogenic metabolite considerably less potent than the hormone Estradiol (E888000).

Background

A hydroxylated metabolite of estradiol or estrone that has a hydroxyl group at C3-beta, 16-alpha, and 17-beta position. Estriol is a major urinary estrogen. During pregnancy, large amount of estriol is produced by the placenta. Isomers with inversion of the hydroxyl group or groups are called epiestriol. Though estriol is used as part of the primarily North American phenomenon of bioidentical hormone replacement therapy, it is not approved for use by the FDA or Health Canada. It is however available in the United States by prescription filled only by compounding pharmacies. It has also been approved and marketed throughout Europe and Asia for approximately 40 years for the treatment of post-menopausal hot flashes.

Indications

Used as a test to determine the general health of an unborn fetus.

What are the applications of Application

Estriol is an estradiol metabolite shown to protect against mammary carcinogenisis

Definition

ChEBI: A 3-hydroxy steroid that is estra-1,3,5(10)-trien-3-ol substituted by additional hydroxy groups at positions 16 and 17 (16alpha,17beta-stereoisomer).

brand name

Theelol (Parke-Davis).

General Description

Estriol, estra-1,3,5(10)-triene-3,16 ,17 -triol, is available for compounding into several differentformulations for use in HRT. It can be used alone or in combinationswith estradiol (Bi-Est) or with estradiol and estrone(Tri-Est).

Hazard

A carcinogen (OSHA).

Pharmacokinetics

Estriol (also oestriol) is one of the three main estrogens produced by the human body. It is only produced in significant amounts during pregnancy as it is made by the placenta. In pregnant women with multiple sclerosis (MS), estriol reduces the disease's symptoms noticeably, according to researchers at UCLA's Geffen Medical School.

Safety Profile

Suspected carcinogen with experimental carcinogenic, neoplastigenic, tumorigenic, and teratogenic data. Other experimental reproductive effects. Mutation data reported. A steroid drug for the treatment of menopause. When heated to decomposition it emits acrid smoke and irritating fumes.

Synthesis

Estriol, estra-1,3,5(10)-trien-3,16|á,17|?-triol (28.1.25), is proposed to be synthesized from the methyl ester of estrone (28.1.8). Methyl ester of estrone is reacted with isopropenylacetate in the presence of p-toluenesulfonic acid, forming the corresponding enolacetate (28.1.23). The resulting enolacetate is oxidized to an epoxide using perbenzoic acid. The resulting epoxide (28.1.24) undergoes reduction by lithium aluminum hydride to.

Metabolism

Purification Methods

Crystallise estriol from EtOH/ethyl acetate. Also purify it by countercurrent distribution with cyclohexane/EtOAc (1:1) and EtOH/H2O (1:1). The UV (EtOH) has max at 280nm ( 2,090 M-1cm-1). [Huffmann & Lott 71 719 1949, Leeds et al. J Am Chem Soc 76 2943 1954, Beilstein 6 IV 7550.]