Measuring estrone in the saliva is an alternative way of measuring the hormone. Estrone measurement is used, inter alia, in the following cases:
- For the laboratory diagnostic approach (among other tests) of early and late puberty in women and to a lesser extent, in men
- For the laboratory diagnostic approach (among other tests) of disorders of the metabolism of sex steroid hormones (eg aromatase deficiency and 17 alpha-hydroxylase deficiency)
- As an adjunct test in the evaluation of osteoporosis, to assess the risk of fractures in postmenopausal women
- For monitoring hormone replacement therapy in postmenopausal women
- For monitoring of anti-estrogen therapy (eg treatment with aromatase inhibitors)
Estrone is one of the three major estrogens produced in humans. Estrone levels are relatively high at birth in both men and women, decrease postnatally and rise again during adolescence. Of the three major estrogens, estrone predominates in postmenopausal women. The estrogenic action of estrone is intermediate compared to that of estriol, the weakest estrogen, and estradiol, the strongest estrogen.
In premenopausal women, estrone is mainly produced by the conversion of androstenedione in the ovaries, with concentrations peaking in the pre-ovulatory phase and with a smaller secondary increase during the luteal phase. In postmenopausal women, in children, and in men, estrone is produced to a large extent by the conversion of androstenedione in peripheral tissues by the action of the enzyme aromatase. Estrone is then converted to estradiol in various tissues by the action of the enzyme 17-beta-hydroxysteroid dehydrogenase and through this conversion, it represents the main source of estradiol in postmenopausal women and in men.
Estrone is the predominant estrogen in postmenopausal women, compared to pre-menopausal estradiol predominance. This is because the production of estradiol by the ovaries decreases significantly after menopause, while the production of estrone by androstenedione changes little compared to pre-menopause. The aromatization of androstenedione to estrone increases with weight gain, as aromatase is abundant in adipose tissue. This increased estrone availability contributes to increasing the circulation of estradiol in obese postmenopausal women.
In non-pregnant women, only about 3% of circulating estrone is not bound to protein. Unbound estrone enters saliva from the blood through intracellular mechanisms and in saliva, most of the estrone remains unbound to proteins. Estrone values in saliva and serum samples are highly correlated.
Measurements of hormones in saliva are an excellent choice, because the collection of the sample is non-invasive and easy, without the possible complications and inconvenience of blood sampling, while ensuring the sensitivity and accuracy of the measurements.