Concentration range of serum sex steroids in normal postmenopausal women and those with diagnosis of vulvovaginal atrophy

Concentrations of endogenous sex steroid hormones and SHBG in healthy postmenopausal women

Studies reporting age-specific reference ranges of endogenous sex steroid hormones in postmenopausal women are relatively scarce. If levels differ by age, dosing and treatment regimens should vary among postmenopausal women accordingly. Our objective was to establish reference ranges for sex steroid hormones and sex hormone binding globulin (SHBG) by age group and overall, and to investigate their association with demographic characteristics. Serum samples were obtained from 1207 healthy postmenopausal women aged 41-92, not using hormone therapy, at the baseline visit of 3 clinical trials. Estrone (E1), estradiol (E2), and total testosterone (T) were measured by radioimmunoassay with preceding purification steps; SHBG was measured by direct chemiluminescent immunoassay. Free T (FT) was calculated. Women were categorized by 5-year age groups. There was little change in the mean estrogen levels among the different age groups (E2: 9-12 pg/mL; E1: 33-35 pg/mL). Mean total T levels increased gradually with age from 19.9-26.2 ng/dL, but FT mean levels were relatively constant (3.7-4.6 pg/mL). Mean SHBG levels increased with age from 43-68 nmol/L. A generalized linear model tested the association of each demographic characteristic with the hormones and SHBG. A significant association was derived. Our study provides valuable insight into the profiles of serum sex steroid hormones and SHBG in different healthy postmenopausal women aged 41-92 years.

Intracrinology and menopause: the science describing the cell-specific intracellular formation of estrogens and androgens from DHEA and their strictly local action and inactivation in peripheral tissues

The secretion of estrogens by the ovaries stops at menopause. Afterward, dehydroepiandrosterone (DHEA) becomes the only source of both estrogens and androgens during all the postmenopausal years. To maintain very low and biologically inactive concentrations of estrogens and androgens in the circulation, DHEA is transformed intracellularly into cell-specific small amounts of estrogens and androgens (except in the endometrium) which then act and are inactivated locally in the same cells, thus avoiding biologically significant systemic exposure to active sex steroids. The secretion of DHEA, however, mainly of adrenal origin, has already decreased by an average of 60% at the time of menopause and it continues to decrease thereafter with a parallel lowering in available intracellular estrogens and androgens. Consequently, after the arrest of estrogen secretion by the ovaries, the loss of DHEA becomes practically responsible for the symptoms and signs of menopause. Replacing what is missing, namely DHEA, at the right place, at the right time, and in the right amount, seems to be the logical and physiological approach for the treatment of menopausal symptoms and signs, as recently demonstrated for pain at sexual activity (dyspareunia), the most bothersome symptom of vulvovaginal atrophy due to menopause.

Systemic estradiol levels with low-dose vaginal estrogens

OBJECTIVES

To critically evaluate published systemic estradiol levels during use of low-dose vaginal estrogens considering detection method and estrogen dose; describe challenges with accurately measuring estradiol; and determine the normal estradiol level range in postmenopausal women.

METHODS

PubMed was searched for studies reporting systemic estradiol levels with lower-dose vaginal estrogens (≤25 μg estradiol or 0.3 mg conjugated equine estrogens). Estradiol levels at baseline and during treatment, area under the curve, and maximum estradiol concentrations were summarized by dose within assay type. A proposed range of systemic estradiol in normal, untreated, postmenopausal women was estimated by conservatively pooling means and standard deviations from published studies.

RESULTS

Mean basal estradiol levels were 3.1 to 4.9 pg/mL using liquid or gas chromatography/mass spectroscopy (LC or GC/MS/MS) with a range of undetectable to 10.5 pg/mL using radioimmunoassay. Systemic estradiol levels with vaginal estrogens reflected their doses as measured with LC or GC/MS/MS in different studies: 7.1 to 9.1 pg/mL and 16.7 to 22.7 pg/mL with a 25-μg softgel capsule insert and a tablet insert, respectively; 4.6 to 7.4 pg/mL and 6.6 to 14.8 pg/mL with a 10-μg softgel capsule and a tablet insert, respectively; and 3.6 to 3.9 pg/mL with a 4-μg softgel capsule insert. A mean systemic estradiol concentration ranging from undetectable to 10.7 pg/mL is proposed as an estimate for basal estradiol levels in normal, untreated, postmenopausal women. Systemic estradiol absorption may be influenced by the placement of estradiol higher (as with an applicator) versus lower (as without an applicator) in the vagina, as estradiol transport to the uterus would be more likely further away than closer to the introitus.

CONCLUSION

Serum estradiol concentrations were generally lower when measured with more specific and sensitive assays. Estradiol absorption was dose-dependent, and may be influenced by dose, formulation, and positioning in the vagina. Very low systemic estradiol absorption with low/ultralow-dose vaginal estrogens may potentially decrease any adverse events that may be associated with higher doses of vaginal estrogens used for treating moderate to severe VVA due to less estradiol exposure.

Female and male serum reference intervals for challenging sex and precursor steroids by liquid chromatography - tandem mass spectrometry

Measuring some sex and precursor steroids is still challenging even by liquid chromatography - tandem mass spectrometry (LC-MS/MS), and few normal values are available. We developed a LC-MS/MS method for estradiol, estrone, dihydrotestosterone and 17-hydroxypregnenolone measurement, compared it with direct immunoassays, and generated sex, age, menopausal and menstrual status specific reference intervals. Liquid-liquid extraction was optimized on 300 μL serum spiked with isotopic internal standards. A 2D-LC system allowed on-line purification and separation in 11 min run. Electrospray ionization was enhanced by ammonium fluoride. MS-detection was obtained by multiple reaction monitoring. Direct ECLIA for estradiol (n = 80) and RIA for estrone (n = 41) were compared with LC-MS/MS. Reference values were estimated in healthy, lean women in reproductive age (n = 118), menopausal women (n = 33) and men (n = 159). The assay showed satisfying imprecision, trueness, recovery and selectivity. Adequate functional sensitivity was achieved for measuring estrone (18.1 pmol/L) and 17-hydroxypregnenolone (117 pmol/L) in all subjects, and estradiol (35.9 pmol/L) and dihydrotestosterone (134 pmol/L) in women in reproductive age and men, but not in menopausal women. Compared with LC-MS/MS, immunoassays showed good agreement for estradiol but severe disagreement for estrone. Estrogens exhibited sex, menopausal and menstrual variations. Dihydrotestosterone and 17-hydroxypregnenolone depended on sex and menopause, the latter also declining with age in men. Strictly defined reference intervals in the adult female and male population were generated for challenging steroids such as estrogens, dihydrotestosterone and 17-hydroxypregnenolone by a novel LC-MS/MS method. Our achievement can be used to deepen the comprehension of several endocrine diseases.