Estrone (3-hydroxy-1,3,5 (10)-estratrien–17-one) is one of the three main naturally occurring estrogens, the others being estradiol and estriol. The estrogens help in the development of female sex organs and secondary sex characteristics.
- Method — ELISA
- Regulatory status — EU: CE
- Substrate/isotope — TMB 450 nm
- Kit size — 12 x 8
- Standard range — 10–300 pg/mL
- Incubation time — 1 x 1 hour, 1 x 15 minutes
- Specimen/volumes — 100 µL Saliva
Bioassay data shows that the estrogenic activity of estrone is much lower when compared to estradiol. Moreover, the physiological function of endogenous estrone is not yet well defined. Estrone is majorly produced from androstenedione.
Over 50% of the estrone is secreted by the ovary in premenopausal women. In prepubertal children, men and postmenopausal women, the major portion of estrone is from peripheral tissue conversion.
At the time of the follicular phase of the menstrual cycle, the estrone level increases with a clear peak around day 13; however, the peak is of short duration, and by day 16 of the cycle, the levels decrease.
Another peak occurs at the luteal phase, around day 21 of the cycle, and in case fertilization does not occur, estrone production decreases again. These estrone concentration changes are in line with that of estradiol.
Estrone originates majorly from maternal sources like the ovaries, adrenals or peripheral conversion until 4 to 6 weeks of pregnancy, thus resting within the normal values. After the 6 to 10 weeks of pregnancy, the values increase slowly because of the placental secretion of estrone.
Estrone levels do not reduce as dramatically as estradiol levels after menopause. Estrone is the major estrogen in postmenopausal women, and in males, the concentration of E1 is seen to rise with age inversely to that of 17-OH-progesterone.
Excessive estrone levels in premenopausal women are due to the conversion of huge amounts of androstenedione secreted in polycystic ovary syndrome and ovarian tumors.