Estrone (E1) | Laboratory research

General Information

Determination of plasma estrone is recommended: for monitoring and diagnostics of delayed puberty (mainly in girls), for diagnostics of sex hormone disorders, in postmenopausal women - for fracture risk assessment, for diagnostics of vaginal bleeding, for determining the need for hormone replacement therapy, for monitoring anti-estrogen therapy.

Estrone (E1) is a representative of the group of estrogenic hormones, which is involved in the formation and maintenance of the female phenotype, the maturation of germ cells in pregnancy. They are also involved in the process of development of the nervous system, bone metabolism, and proper functioning of the endothelium of blood vessels. In the body of an adult woman (non-pregnant), estrogens are represented by: estrone (E1) and estradiol (E2). The third estrogen - estriol (E3) - is mainly present during pregnancy. After menopause, E1 (estrone) is the main estrogen, and E2 and E3 levels decrease significantly.

Estrogens are involved in the formation and maintenance of the female phenotype and in the process of pregnancy. Their role is important in other processes as well, such as: growth, maturation of the nervous system, bone metabolism and maintenance of the physiological function of the endothelium. In the body of an adult woman (non-pregnant), estrogens are represented by: estrone (E1) and estradiol (E2). The third estrogen - estriol (E3) - is mainly present during pregnancy. After menopause, E1 (estrone) is the main estrogen, and E2 and E3 levels decrease significantly.

Estradiol is mainly produced by the aromatization of testosterone in the ovaries and testes. A small amount is produced in the adrenal glands and peripheral adipose tissue.

In contrast, the base fraction of estrone is produced in the adrenal glands by aromatization of androstenedione. Estrone and estradiol can be interconverted, and both can be inactivated by hydroxylation and conjugation. The circulating amount of estradiol in the blood of non-menopausal, non-pregnant women is 1,5-4 times higher than estrone.

Estradiol levels are much lower in men and postmenopausal women, while estrone levels are less variable, leading to changes in the estradiol/estrone ratio at different times.

Estradiol levels in premenopausal women vary according to the phases of the menstrual cycle. In the early follicular phase, its level is low, it begins to increase 2-3 days before ovulation, and it increases rapidly during ovulation and reaches its maximum level before the peak of malutheinizing hormone. This is followed by a slow decline during ovulation. After that, estradiol increases again until the middle of the luteal phase and then decreases to a minimum, then until the follicular phase.

Determination of estradiol is an essential part of the assessment of female reproductive function, infertility, oligo-amenorrhea and menopause. It is also used to monitor ovulation in preparation for in vitro fertilization.

When should we do the research?

Precocious or delayed puberty (predominantly in girls)

In disorders of the metabolism of sex hormones

To assess fracture risk in postmenopausal women

When monitoring hormone replacement therapy

When monitoring anti-estrogen therapy

Material for examination: Venous blood

Reference norms

In men  15-65 pg/ml (picograms per milliliter)

In pregnant women

• First trimester of pregnancy: 155 – 30.77 pg/ml
• Second trimester of pregnancy: 408 – 62.15 pg/ml

In women:

When taking oral contraceptives: 48.0 – 342.4 pg/ml

Follicular phase: 36.1 – 156.5 pg/ml

Lutein phase: 47.3 – 198.1 pg/ml

Pre-ovulation phase: 57.9 – 255.9 pg/ml

Postmenopause on the background of estrogen therapy: 50.9 – 487.5

Postmenopause without hormone therapy: 30.9 – 99.8

Interpretation

Irregular cycles or absence of cycles with normal or high estradiol levels and increased estrone levels may indicate polycystic ovary syndrome, androgen-producing tumors, estrogen-producing tumors.

Gynecomastia, or other manifestations of feminization in men, is the result of an absolute or relative excess of estrogens in relation to androgens. The reasons for the increase of estrone and estradiol may be:

• An excess of androgens due to cancer or androgen therapy, accompanied by an excess of estrogens.
• Obesity - with hyperproduction of estrone
• Disruption of estrone and estradiol absorption processes - in liver diseases
• Estrogen-producing tumors
• Estrogen therapy with synthetic estrogen.