Oestradiol in saliva during the menstrual cycle

Effects of sex and menstrual cycle on sweating during isometric handgrip exercise and postexercise forearm occlusion

NEW FINDINGS

What is the central question of this study? Do sex and menstrual cycle modulate sweating during isometric handgrip exercise and muscle metaboreceptor stimulation? What is the main finding and its importance? Sex modulates sweating during isometric handgrip exercise, as indicated by the lower sweat output per gland in women than in men, but not during muscle metaboreceptor stimulation. Sweat output per gland during isometric handgrip exercise and muscle metaboreceptor stimulation were lower in the mid-luteal phase than in the early follicular phase in women. Cholinergic sweat gland sensitivity might explain, in part, the individual variation of the response. Our results provide new insights regarding sex- and menstrual cycle-related modulation of the sweating response.

ABSTRACT

We investigated whether sex and menstrual cycle could modulate sweating during isometric handgrip (IH) exercise and muscle metaboreceptor stimulation. Twelve young, healthy women in the early follicular (EF) and mid-luteal (ML) phases and 14 men underwent two experimental sessions consisting of a 1.5 min IH exercise at 25 and 50% of maximal voluntary contraction (MVC) in a hot environment (35°C, relative humidity 50%) followed by 2 min forearm occlusion to stimulate muscle metaboreceptors. Sweat rates, the number of activated sweat glands and the sweat output per gland (SGO) on the forearm and chest were assessed. Pilocarpine-induced sweating was also assessed via transdermal iontophoresis to compare the responses with those of IH exercise and muscle metaboreceptor stimulation, based on correlation analysis. Sweat rates on the forearm and chest during IH exercise and muscle metaboreceptor stimulation did not differ between men and women in either menstrual cycle phase (all P ≥ 0.144). However, women in both phases showed lower SGO on the forearm and/or chest compared with men during IH exercise at 50% of MVC, with no differences in muscle metaboreceptor stimulation. Women in the ML phase had a lower forearm sweat rate during IH exercise at 50% of MVC (P = 0.015) and SGO during exercise and muscle metaboreceptor stimulation (main effect, both P ≤ 0.003) compared with those in the EF phase. Overall, sweat rate and SGO during IH exercise and muscle metaboreceptor stimulation were correlated with pilocarpine-induced responses (all P ≤ 0.064, r ≥ 0.303). We showed that sex and menstrual cycle modulate sudomotor activity during IH exercise and/or muscle metaboreceptor stimulation. Cholinergic sweat gland sensitivity might explain, in part, the individual variation of the response.

Salivary steroid assays – research or routine?

Salivary concentrations of unconjugated steroids reflect those for free steroids in serum although concentrations may differ because of salivary gland metabolism. Samples for salivary steroid analysis are stable for up to 7 days at room temperature, one month or more at 4°C and three months or more at −20°C. When assessed against strict criteria, the evidence shows that salivary cortisol in evening samples or following dexamethasone suppression provides a reliable and effective screen for Cushing's syndrome. Sequential salivary cortisol measurements are also extremely helpful for the investigation of suspected cyclical Cushing's syndrome. There is potential for the identification of adrenal insufficiency when used with Synacthen stimulation. Salivary 17-hydroxyprogesterone and androstenedione assays are valued as non-invasive tests for the home-monitoring of hydrocortisone replacement therapy in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The diagnostic value of salivary oestradiol, progesterone, testosterone, dehydroepiandrosterone and aldosterone testing is compromised by rapid fluctuations in salivary concentrations of these steroids. Multiple samples are required to obtain reliable information, and at present the introduction of these assays into routine laboratory testing is not justified.

The interrelationships among sex hormone concentrations, motoneuron excitability, and anterior tibial displacement in women and men

CONTEXT

Sex hormone fluctuations have been implicated as a contributing factor to the high rates of noncontact injury to the anterior cruciate ligament in females.

OBJECTIVE

To determine the strength of the relationships among variables of sex hormone concentrations, motoneuron excitability, and anterior tibial displacement (ATD) in women and men and to determine if these relationships differ between the sexes.

DESIGN

Cohort study.

SETTING

Sports medicine laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-eight regularly menstruating women (age = 22.4 +/- 3.4 years) and 15 men (age = 22.3 +/- 3.7 years) participated in the study.

INTERVENTION(S)

Fluctuations in sex hormones were determined for the participants. Female participants were tested every other day of their menstrual cycles, whereas male participants were tested every fourth day during the 28-day period.

MAIN OUTCOME MEASURE(S)

We measured Hoffmann reflexes (maximum Hoffmann reflex [H(max)] to maximum M-wave [M(max)] ratio in the soleus), ATD under a 134-N load, and saliva concentrations of estrogen and progesterone. The independent variable was sex. Pearson product moment correlation coefficients were calculated for each participant by pairing measurements made on the same day. Two-tailed independent-samples t tests were used to determine the difference between the male and female correlations for each variable.

RESULTS

Over the course of the study, the relationships between H(max)ratioM(max) and estrogen, H(max)ratioM(max) and progesterone, ATD and estrogen, and ATD and progesterone were not different between the sexes. However, the relationship between ATD and progesterone was different between the sexes (P = .036).

CONCLUSIONS

The observed correlations did not support our hypothesis that the relationships between sex hormone levels and reflex activity or between sex hormone levels and ATD would be different for women compared with men. If sex hormone concentrations significantly contribute to anterior cruciate ligament ruptures because of changes in laxity or in motoneuron excitability, their mechanism of action is likely multifactorial and complex.

Skin tissue water and laser Doppler blood flow during a menstrual cycle

Previous work offers conflicting evidence concerning whether basal skin blood flow (SBF) varies with the menstrual cycle. Our goal was to determine the extent of cycle-dependent changes in forearm SBF parameters and if they are linked to local tissue water content and arm volume changes. Both arms of 10 premenopausal women were evaluated three times during their cycle (days 4, 12 and 22) and 10 postmenopausal women were evaluated once. Each evaluation included laser Doppler blood flow parameters (perfusion, volume and velocity), skin temperature, arm volume and local tissue water determined by a new tissue dielectric constant method. Estradiol and progesterone concentrations were determined at each visit by using saliva samples and analysis showed the expected pattern of variation over the cycle. Main results showed no significant cycle-dependent variations in any SBF parameter, temperature, tissue water or arm volume. Postmenopausal women had significantly less estradiol levels, but did not differ with respect to premenopausal women in any measured parameter except for a slightly less blood velocity (P<0.01). We hypothesize that that the absence of changes in tissue water and arm volume in our group may account for the constancy of the measured SBF parameters. However, in other populations, hormonally induced tissue changes may occur and contribute to the cycle-dependent changes in resting blood perfusion that have been reported. This possibility suggests that it may be useful to measure and report a skin tissue water index when serial changes in blood perfusion are being investigated.

The diagnostic applications of saliva--a review

This review examines the diagnostic application of saliva for systemic diseases. As a diagnostic fluid, saliva offers distinctive advantages over serum because it can be collected non-invasively by individuals with modest training. Furthermore, saliva may provide a cost-effective approach for the screening of large populations. Gland-specific saliva can be used for diagnosis of pathology specific to one of the major salivary glands. Whole saliva, however, is most frequently used for diagnosis of systemic diseases, since it is readily collected and contains serum constituents. These constituents are derived from the local vasculature of the salivary glands and also reach the oral cavity via the flow of gingival fluid. Analysis of saliva may be useful for the diagnosis of hereditary disorders, autoimmune diseases, malignant and infectious diseases, and endocrine disorders, as well as in the assessment of therapeutic levels of drugs and the monitoring of illicit drug use.

Direct colorimetric monoclonal antibody enzyme immunoassay for estradiol-17β in saliva

We developed a direct microtiter plate enzyme immunoassay to measure estradiol-17β in saliva. The assay has a commercially available monoclonal antibody, raised against estradiol-17β–6-carboxymethyloxime–bovine serum albumin, and a homologous horseradish peroxidase conjugate measured colorimetrically. The detection limit (equivalent to B0 − 3 SD) is 365 amol/well or 7.3 pmol/L when 50-μL samples are assayed. Cross-reactivity with estrone and estriol, testosterone, or progesterone is &lt;0.2%. Estradiol-17β was measured in daily samples over five natural menstrual cycles and eight cycles stimulated as a preliminary to in vitro fertilization, and the concentrations and fluctuations found agreed with previously published data. This method gives results in ∼3 h and may be useful for fertility monitoring and management.

The monitoring of the menstrual status of female athletes by salivary steroid determination and ultrasonography

This study was designed to evaluate whether traditional plasma hormone determinations can be adequately replaced by measurements of salivary hormones. Eleven young sportswomen with menstrual irregularities attributed to strenuous physical exercise participated in this study. Mean body weight expressed as a percentage of ideal body weight was 92%, SD 4%. Their mean weekly training distance was 35 km, SD 15. Basal plasma endocrinological measurements revealed a hypo-oestrogenic status (mean plasma oestradiol values: 22 pg.ml-1, SD 8.8), and a deficient luteal phase (mean plasma progesterone: 2.9 ng.ml-1, SD 2.1). Pre-exercise salivary sex steroids were low. Salivary progesterone levels were 39.3 pg.ml-1, SD 9.5 (normal ranges in saliva: 25-60 pg.ml-1), salivary oestrone (E1) was 12.2 pg.ml-1, SD 2.3 (normal ranges in saliva: 7.5-25 pg.ml-1), and salivary oestradiol (E2) less than 1.9 pg.ml-1, SD 1.1 (normally 1.0-10.0 pg.ml-1). After a 21-km run, all salivary steroids appeared to increase. Mean salivary testosterone levels increased by 15.2% and salivary progesterone by 14.8%. Mean salivary oestrogens also increased (E1: +13.9%; E2: +21.1%). These findings confirm the results of earlier studies which found higher post-exercise plasma sex steroid levels. Since salivary measurements are believed to reflect non-protein-bound, thus free steroid levels, the results obtained by these techniques may provide a more realistic picture of the hormonal effects of physical exercise. In future, more accurate, cost-effective and easier techniques for salivary measurements may offer additional advantages.

Salivary estradiol and progesterone during the normal ovulatory menstrual cycle in Chinese women

Salivary and serum levels of estradiol and progesterone were measured by radioimmunoassay in 10 Chinese women during their normal menstrual cycles. Changes in salivary estradiol and progesterone levels followed a similar pattern to that in the serum. Significant correlation was found between salivary and serum levels of estradiol and progesterone (p less than 0.001). Measurements of these salivary steroids may be used to assess follicular dynamics. Moreover, salivary sampling is simple, convenient and stress free.

Progesterone and estradiol in saliva after in vitro fertilization and embryo transfer

The importance of the luteal function to ensure adequate implantation prompted us to assay salivary estradiol (SE2) and salivary progesterone (SP) concentration serially after embryo transfer by simple and rapid radioimmunoassays to allow a noninvasive easily repeatable approach. SE2, which has fallen 1 day after human chorionic gonadotropin injection, increased after reimplantation (day 3), plateaued during approximately 1 week, and returned to basal levels before menstruation in absence of conception or in chemical pregnancy, whereas it increased steadily in successful pregnancy. SP increased in all the cases, formed a plateau, and returned progressively to basal levels before menstruation, whereas in ongoing pregnancy there was a transitory decline in the midluteal phase followed by a rapid and continuous increase, with a significantly higher ratio day 13/day 10 in successful pregnancy.

The measurement of hormones in saliva: possibilities and pitfalls

The easy stress-free, non-invasive nature of saliva collection makes it one of the most accessible body fluids and it is potentially of value in studying normal human physiology as well as pathology. Measurements of salivary hormone levels will usually only be of value if they reflect the plasma level of the hormone and the relationship between the saliva and plasma levels of many hormones have been studied by a number of groups. The measurement of the salivary level is a valuable clinical tool for some hormones (e.g. cortisol, oestriol, progesterone), is of little value for others (e.g. cortisone, dehydroepiandrosterone sulphate, thyroxine, pituitary hormones) and for many others the saliva/plasma relationship is not yet sufficiently understood to assess the value of the salivary measurement. As well as reviewing the state of our knowledge of the salivary concentration of many hormones this review outlines a number of "rules of thumb" concerning the presence of hormones in saliva, their saliva/plasma relationship and the potential usefulness of assays of their salivary concentration.

Salivary oestradiol and progesterone levels in premenopausal women with breast cancer

The concentrations of oestradiol and progesterone have been measured in salivary specimens collected daily over a complete menstrual cycle in 12 patients with operable breast cancer and 12 normal control volunteers. There was no significant difference (P greater than 0.05) for either hormone between these two groups. Both showed a mid-cycle rise in oestradiol levels followed by a smaller but sustained increase during the luteal phase. The progesterone concentration increased markedly during the luteal phase of the cycle. Total or non-protein bound oestradiol levels measured in blood samples from 19 normal women were both linearly correlated (P less than 0.001) with the concentration of oestradiol in matched saliva samples. The amount of free oestradiol in blood was about twice that found in saliva.

Hormones in saliva

Since the collection of saliva is noninvasive, nonstressful and usually very convenient there have been many recent studies examining the clinical relevance of measuring various hormones in saliva. It now appears that the measurement of most unconjugated steroids in saliva will provide clinically useful data whereas the measurement of conjugated steroids, thyroid hormones, and protein hormones is unlikely to be clinically relevant. The key factors determining whether the salivary concentration of a hormone or drug is likely to be clinically relevant are the mechanisms by which the material enters the saliva; the "free to protein bound" ratio for the material; and the structure of the material, i.e., its molecular weight, polarity and the presence of ionizable groups.

Estradiol in saliva for monitoring follicular stimulation in an in vitro fertilization program

A rapid and sensitive radioimmunoassay (RIA) was developed to compare serum and saliva estradiol (E2) levels in patients undergoing ovulation induction in an in vitro fertilization and embryo transfer (IVF-ET) program. Serum and saliva E2 were compared in 23 patients. The sensitivity of the saliva RIA standard curve was 11 fmol/tube (equal to 3.2 pg/tube). There was a highly significant correlation between serum and saliva E2 throughout the stimulated cycles (r = 0.769; P less than 0.001). The ratio of serum to saliva E2 was constant throughout the stimulated cycles (1.7% +/- 0.3%, mean +/- standard deviation [SD]). The E2 concentration per follicle was 1548 pmol/l in serum and 23 pmol/l in saliva. Mean E2 levels in saliva (+/- SD) were 74 +/- 21 pmol/l at midcycle and 46 +/- 12 pmol/l at midluteal phase. The findings indicate that measurement of saliva E2 provides a reliable, noninvasive method and may replace serum measurements for monitoring stimulated cycles in an IVF-ET program.

Progesterone and estradiol in the saliva and plasma during the menstrual cycle

Plasma and salivary progesterone and estradiol were measured throughout nine menstrual cycles and before and after intramuscular injection of progesterone in four women. Mean +/- standard error of the mean (SE) salivary progesterone increased significantly from 238.7 +/- 14.3 pg/ml in the proliferative phase to 475.3 +/- 39.8 pg/ml in the secretory phase (p less than 0.001). There was a highly significant correlation between plasma and salivary progesterone levels throughout the menstrual cycle (r = 0.5841, p = 0.001). The ratio of plasma to salivary progesterone was 6.4 during the proliferative phase and increased to 26.7 during the secretory phase. Free unbound progesterone as determined by equilibrium dialysis gave a mean +/- SE level of 126.8 +/- 6.9 pg/ml during the proliferative phase and increased significantly to 196.8 +/- 18.8 pg/ml during the secretory phase (p less than 0.001). The corresponding levels in the plasma were 88.5 +/- 11.2 pg/ml, which increased significantly to 332.2 +/- 39.2 pg/ml (p less than 0.001). Free progesterone constituted 53.7% and 41.4% of salivary progesterone during the proliferative and secretory phases, respectively, whereas the corresponding percentages in the plasma were 5.8% and 2.6%. Both plasma and salivary progesterone levels increased in a dose-dependent manner after an intramuscular injection of progesterone, with peak levels being attained from 2 to 3 hours after the injection. Salivary estradiol levels were 5 to 18 and 8 to 35 pg/ml in the proliferative and secretory phases, respectively, but showed no correlation with plasma estradiol levels. The findings are discussed in relationship to the origin of salivary progesterone and the potential use of it as an index of ovulation.