Estron

Estron (E1) is one of the two main estrogens of the ovary, the primary estrogen being estradiol (E2). Only 45% of circulating estrone comes from the ovaries, about 5% from the adrenal glands and 50% from extraglandular sources, mainly from the subcutaneous fatty tissue. There it is formed from androstendione, catalysed by P-450 aromatase. Estron has a lower estrogenic effectiveness than estradiol.

The extragonadal conversion of androstendione to estrone, which takes place to a high degree in the fatty tissue, means that obese patients tend to produce more.

Estron (E1) is broken down in the liver and excreted in bile and urine. Extragonadal conversion is the main source of circulating estrogens in postmenopausal women. Changes in the estradiol/estroneratio reflect the ovarian aging process and the development of menopause.

Normal values (method: RIA)

Men (reference rangepg/ml):

• 15.0 - 65.0 pgml

Women (reference range pg/ml):

• folicular phase: 36.1 - 156.5 pg/ml
• Periovulatory: 57,9 - 255,9 pg/ml
• Luteal phase: 47,3 - 198,1 pg/ml
• Oral contraceptives: 48.0 - 342.4 pg/ml
• Pregnancy:
  • 1st SS trimester: 155 - 3077 pg/ml
  • 2nd SS trimester: 408 - 6215 pg/ml
• Postmenopausal (ÖT*=estrogen replacement therapy):
  • postmenopausal without ÖT*: 50,9 - 487,5 pg/ml
  • postmenopausal with ÖT*: 30,9 - 99,8 pg/ml

Indication: Assessment of estrogen status in postmenopausal women.

Elevated values

• Post-menopausal (through peripheral transformation), obesity, increasing age,
• Luteal phase of the menstrual cycle, pregnancy.
• Taking estrogenic drugs.

Decreased values:

• Advanced menopause,
• Hypogonadism
• Cave: Correlation with osteopenia

RIA; Material Serum, EDTA plasma or heparin plasma, 1 mL, refrigerated 4 - 8 °C

The determination of estrone in the blood is an important laboratory measurement to exclude estrogen deficiency in postmenopause.

1. Böhm C et al (2017) in: Neumeister B et al. clinical guide to laboratory diagnostics. Urban&Fischer Publisher Munich S. 340-341