A factor analysis approach to examining relationships among ovarian steroid concentrations, gonadotrophin concentrations and menstrual cycle length characteristics in healthy, cycling women.

STUDY QUESTION: How are ovarian steroid concentrations, gonadotrophins and menstrual cycle characteristics inter-related within normal menstrual cycles? SUMMARY ANSWER: Within cycles, measures of estradiol production are highly related to one another, as are measures of progesterone production; however, the two hormones also show some independence from one another, and measures of cycle length and gonadotrophin concentrations show even greater independence, indicating minimal integration within cycles. WHAT IS KNOWN ALREADY: The menstrual cycle is typically conceptualized as a cohesive unit, with hormone levels, follicular development and ovulation all closely inter-related within a single cycle. Empirical support for this idea is limited, however, and to our knowledge, no analysis has examined the relationships among all of these components simultaneously. STUDY DESIGN, SIZE, DURATION: A total of 206 healthy, cycling Norwegian women participated in a prospective cohort study (EBBA-I) over the duration of a single menstrual cycle. Of these, 192 contributed hormonal and cycle data to the current analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Subjects provided daily saliva samples throughout the menstrual cycle from which estradiol and progesterone concentrations were measured. FSH and LH concentrations were measured in serum samples from three points in the same menstrual cycle and cycle length characteristics were calculated based on hormonal data and menstrual records. A factor analysis was conducted to examine the underlying relationships among 22 variables derived from the hormonal data and menstrual cycle characteristics. MAIN RESULTS AND THE ROLE OF CHANCE: Six rotated factors emerged, explaining 80% of the variance in the data. Of these, factors representing estradiol and progesterone concentrations accounted for 37 and 13% of the variance, respectively. There was some association between measures of estradiol and progesterone production within cycles; however, cycle length characteristics and gonadotrophin concentrations showed little association with any measure of ovarian hormone concentrations. LIMITATIONS, REASONS FOR CAUTION: Our summary measures of ovarian hormones may be imprecise in women with extremely long or short cycles, which could affect the patterns emerging in the factor analysis. Given that we only had data from one cycle on each woman, we cannot address how cycle characteristics may covary within individual women across multiple cycles. WIDER IMPLICATIONS OF THE FINDINGS: Our findings are generalizable to other healthy populations with typical cycles, however, may not be applicable to cycles that are anovulatory, extreme in length or otherwise atypical. The results support previous findings that measures of estradiol production are highly correlated across the cycle, as are measures of progesterone production. Estradiol and progesterone concentrations are associated with one another, furthermore. However factor analysis also revealed more complex underlying patterns in the menstrual cycle, highlighting the fact that gonadotrophin concentrations and cycle length characteristics are virtually independent of ovarian hormones. These results suggest that despite integration of follicular and luteal ovarian steroid production across the cycle, cycle quality is a multi-faceted construct, rather than a single dimension. STUDY FUNDING/COMPETING INTEREST(S): The EBBA-I study was supported by a grant from the Norwegian Cancer Society (49 258, 05087); Foundation for the Norwegian Health and Rehabilitation Organizations (59010-2000/2001/2002); Aakre Foundation (5695-2000, 5754-2002) and Health Region East. The current analyses were completed under funding from the National Institutes of Health (K12 ES019852). No competing interests declared.

Higher luteal progesterone is associated with low levels of premenstrual aggressive behavior and fatigue.

Contradictory findings show both positive and negative effect of progesterone on the premenstrual mood changes in women. Here we present the study investigating this relationship on the large sample of premenstrual women. 122 healthy, reproductive age women collected daily morning saliva samples and recorded intensity scores for the mood symptoms: irritability, anger, sadness, tearfulness, insomnia, and fatigue. Saliva samples were assayed for progesterone concentrations and mood intensity scores were used to calculate behavioral indices. Women with low Aggression/Irritability and Fatigue had consistently higher progesterone levels during the luteal phase than women with high Aggression/Irritability and Fatigue. Additionally, Aggression/Irritability and Fatigue correlated negatively with maximal progesterone value during the luteal phase. Our results demonstrated a negative effect of low progesterone level on the premenstrual mood symptoms such as aggressive behavior and fatigue in healthy reproductive age women. This supports a previously proposed model of biphasic action of progesterone metabolites on mood.

Ovarian hormones and reproductive risk factors for breast cancer in premenopausal women: the Norwegian EBBA-I study.

BACKGROUND: Ovarian hormones, parity and length of 'menarche-to-first birth' time interval are known risk factors for breast cancer, yet the associations between 17ß-estradiol, progesterone and these reproductive factors remain unclear. METHODS: A total of 204 women (25-35 years) who participated in the Norwegian EBBA-I study collected daily saliva samples for one complete menstrual cycle, and filled in a reproductive history questionnaire. Anthropometry was measured and saliva samples were analyzed for ovarian hormones. Associations between parity, the interval and ovarian hormones, and effects of hormone-related lifestyle factors were studied in linear regression models. RESULTS: Mean age was 30.7 years, and age of menarche 13.1 years. Parous women had on average 1.9 births, and age at first birth was 24.5 years. No association was observed between parity and ovarian steroids. In nulliparous women, higher waist circumference (≥ 77.75 cm) and longer oral contraceptive (OC) use (≥ 3 years) were associated with higher levels of 17ß-estradiol. Short (<10 years) versus long (>13.5 years) 'menarche-to-first birth' interval was associated with higher overall mean (P(trend) = 0.029), 47% higher maximum peak and 30% higher mid-cycle levels of 17ß-estradiol. We observed a 2.6% decrease in overall mean salivary 17ß-estradiol with each 1-year increase in the interval. CONCLUSIONS: Nulliparous women may be more susceptible to lifestyle factors, abdominal overweight and past OC use, influencing metabolic and hormonal profiles and thus breast cancer risk. Short time between 'menarche-to-first birth' is linked to higher ovarian hormone levels among regularly cycling women, suggesting that timing of first birth is related to fecundity.

Body fat, energy balance and estradiol levels: a study based on hormonal profiles from complete menstrual cycles.

BACKGROUND: Female fecundity is regulated by nutritional status. Although widely cited, this hypothesis is not strongly supported by empirical data from non-obese, healthy women of reproductive age. METHODS: Healthy, reproductive aged women (n = 141) from Southern Poland collected daily morning saliva samples for one complete menstrual cycle. Levels of 17-beta-estradiol were analyzed by radioimmunoassay. Anthropometric measurements, including body fat percentage, were taken randomly with respect to phase of the menstrual cycle. Energy balance was specified based on changes in body fat percentage from the beginning to the end of the observation period. RESULTS: Women with very low and high body fat had significantly lower levels of E2 compared with women with low and average body fat. In women of very low to average body fat, a 10% increase in body fat was associated with a 5-7 pmol/l increase in estradiol levels. The association between fat percentage and E2 was even stronger in women with positive energy balance, who also showed significant differences between body fat groups in estradiol profiles across whole the menstrual cycle. No such relationship was found in women with negative energy balance. CONCLUSIONS: In healthy women, we found a non-linear association between body fat and estradiol levels. Both very low and high body fat was associated with decreased estradiol levels. The relationship between estradiol and body fat was strongly influenced by women's energy balance.

Men in committed, romantic relationships have lower testosterone.

Variation in human male testosterone levels may reflect, and effect, differential behavioral allocation to mating and parenting effort. This proposition leads to the hypothesis that, among North American men, those involved in committed, romantic relationships will have lower testosterone levels than men not involved in such relationships. Our study is the first to examine whether being in such a relationship (rather than being married) is the meaningful predictor of male testosterone levels. To test this hypothesis, 122 male Harvard Business School students filled out a questionnaire and collected one saliva sample (from which testosterone level was measured). Results revealed that men in committed, romantic relationships had 21% lower testosterone levels than men not involved in such relationships. Furthermore, the testosterone levels of married men and unmarried men who were involved in committed, romantic relationships did not differ, suggesting that, at least for this sample, male pair bonding status is the more significant predictor of testosterone levels than is marital status.

Symptom fluctuation in bulimia nervosa: relation to menstrual-cycle phase and cortisol levels.

BACKGROUND: Individuals with bulimia nervosa report significant symptom fluctuation, and some studies have suggested a premenstrual exacerbation of binge frequency. The purpose of this study is to explore the hormonal correlates of symptom fluctuation in bulimia nervosa. METHOD: For five consecutive weeks (one full menstrual cycle), eight women with bulimia nervosa and eight non-eating-disordered control women collected morning saliva samples and recorded several mood characteristics; the bulimic women also recorded binge and purge episodes. Subsequently, salivary cortisol and androgen levels were determined by radioimmunoassay. RESULTS: Bulimic symptoms were exacerbated in both the mid-luteal and premenstrual phases, when compared with the follicular and ovulatory phases (F(3,21) = 3.76, P = 0.026; contrast analysis t(7) = 3.47, P < 0.01). Fluctuation in cortisol was closely correlated with fluctuation of bulimic symptoms, with elevatedcortisol secretion following symptom exacerbation (r(24) = 0.64, P = 0.001). CONCLUSIONS: Bulimic symptom fluctuation appears to be related to two hormonal phenomena--phase of the menstrual cycle and cortisol secretion--with menstrual-cycle phase influencing bulimic symptom severity, and bulimic symptom severity effecting increases in cortisol secretion. Improved understanding of the hormonal causes and consequences of symptom fluctuation may lead to improved psychological and pharmacological treatments for bulimia nervosa.

Comparison of salivary steroid profiles in naturally occurring conception and non-conception cycles.

Oestradiol and progesterone profiles from naturally occurring conception and exposed non-conception cycles were compared to assess the impact of natural variation in concentrations of ovarian steroid hormones on female fecundity. In a prospective, longitudinal study, 24 women collected saliva samples twice daily and recorded intercourse for up to 1 year or until a pregnancy was clinically confirmed. Oestradiol and progesterone concentrations were measured by a salivary radioimmunoassay. Average mid-follicular oestradiol concentrations were significantly higher in conception than in non-conception cycles (12.6 +/- 1.7 versus 8.5 +/- 0.6 pmol/l, P < 0.01). A separate analysis, including only cycles from those women who contributed both conception and non-conception cycles, demonstrated an even more pronounced difference in mid-follicular oestradiol concentrations, not just for conception and non-conception cycles as groups (14.5 +/- 2.3 versus 6.5 +/- 0.7 pmol/l, P < 0.001), but also between the conception and average non-conception concentrations of individual women. Among these women, relative mid-follicular oestradiol concentration was highly correlated with the probability of successful conception. In addition, relative body weight was significantly positively correlated with mid-follicular oestradiol concentration. These findings indicate that variation in follicular development, reflected in variation in follicular oestradiol concentrations, is an important indicator of fecundity.

Reference values for luteal progesterone measured by salivary radioimmunoassay.

OBJECTIVE: To establish age-stratified reference values for salivary luteal P levels. DESIGN: One hundred thirty-six regularly menstruating women (18 to 48 years of age), screened for weight, exercise, and steroid medication use, collected daily saliva samples for one complete menstrual cycle. Luteal P levels were measured by 3H-RIA, and data were aligned by day of next menstrual onset. Means (+/- 1 SD range) and percentiles, calculated using both untransformed and log transformed data, were calculated for each luteal day and for indices of luteal P production. RESULTS: Reference values for salivary daily luteal P levels and indices of luteal P are presented for three age groups (18 to 24 years, 25 to 39 years, and 40 to 48 years). CONCLUSION: The age-stratified reference values presented here can be used, without collateral clinical procedures, to assess salivary luteal P levels. Salivary monitoring is ideally suited for research and long-term clinical observation, but the characteristics of salivary P data may limit the usefulness of these values for individual diagnosis.

The ecological context of human ovarian function.

New methods for monitoring ovarian function have allowed an extension of research venue beyond typical clinical settings to studies of human populations in their natural settings. Such studies have confirmed that patterns of variation in ovarian function with age and energetic factors are general features of human reproductive biology. Age patterns of ovarian function are extremely robust across populations of distinct genetic, ecological and cultural backgrounds. Comparable ovarian responses to energetic stresses are likewise observable in different populations where they arise as correlates of local ecologies rather than as correlates of voluntary patterns of diet or exercise. Maternal age and energetic factors also appear to interact with lactation in the modulation of postpartum, ovarian function. Average levels of ovarian function, however, differ considerably between populations, perhaps correlated with chronic environmental conditions that affect growth, development, and the establishment of adult set-points. Western populations appear to represent an extreme of the spectrum of variation in ovarian function, a fact which may relate to the epidemiology of breast and ovarian cancer.

Normative study of age variation in salivary progesterone profiles.

Daily luteal progesterone levels were measured for 124 regularly menstruating women, aged 18-44, by radioimmunoassay of steroid levels in saliva. A consistent pattern of age variation in luteal function was found, with the lowest levels of progesterone in the 18-19-year-old and 40-44-year-old groups, the highest values in the 25-34 year olds, and intermediate values in the 20-24 and 35-39-year-old groups. The striking similarity of this pattern of age variation with empirically and theoretically generated curves of apparent fecundability, suggests that age-related changes in ovarian function may underlie observed age variation in fecundability.

PIP: Daily salivary progesterone levels were determined by radioimmunoassay in 124 women aged 18-44 with regular menstrual cycles, and the superimposed luteal progesterone profiles were compared by age group. Salivary progesterone correlated with serum progesterone (correlation coefficient 0.80.-0.97. The subjects were screened for regular cycles of 22-38 days, normal body weight, and no weight loss or vigorous exercise, or recent oral contraceptives or pregnancy. The age groups of 20-24 to 35-39 consistently showed highest average progesterone levels, average mid-luteal progesterone, peak progesterone, number of days with progesterone over 300 pmol/1, and ovulatory frequency. The day of peak progesterone level was latest in the youngest women aged 18-19, earliest in those age 30-34, and intermediate in the other groups. There was a gradual, continuous progression and regression in luteal function with age over the reproductive span. The implications of this gradual change in ovarian function for studies in human biology, not only for carefully screened healthy Americans, but also for populations living in harsher ecological conditions, are discussed.

Salivary testosterone levels in males from the Ituri Forest of Zaïre.

Morning and evening testosterone levels were measured in the saliva of Efe pygmies (N = 11) and Lese villagers (N = 18) living in the Ituri Forest of northeast Zaïre and compared with levels in Boston controls (N = 10). With one exception, levels in the individual Zaïrois subjects fall within the normal ranges reported for Western clinical populations. Daily variation in the Zaïrois subjects (a.m./p.m. ratio = 1.32 for Efe, 1.22 for Lese) is also comparable to both the Boston controls (1.61) and values reported by other researchers for Western subjects. Average morning levels for the Zairois subjects (420 pmol/liter for Efe, 341 pmol/liter for Lese), however, fall significantly below the average for the Boston subjects (589 pmol/liter; Efe, P <0.05; Lese, P <0.01). A correlation between morning testosterone level and height is observed for the Lese sample (r=0.76, P <0.005). Similar correlations have not been reported for Western subjects. Possible roles of acute and chronic environmental conditions in generating these observations are noted. This study demonstrates the potential utility of salivary steroid assays for investigating questions related to male gonadal function under field conditions.

Development of protocols for the application of salivary steroid analysis to field conditions.

The simple and noninvasive nature of sample collection for salivary steroid assay makes this technique well suited for anthropological field studies of human reproduction function. In this study, a series of controlled experiments was done to investigate the effects of modifying common clinical sample collection and storage procedures for field use. Matched sets of samples were assayed for four steroids to test the effects of using plastic, rather than glass, collection tubes, of using a stimulant to aid collection, and of storing samples at ambient temperature rather than frozen. Our work confirms the feasibility of collecting samples for salivary steroid assay in field situations, while at the same time emphasizing the importance of considering methodological issues in planning and interpreting such studies. Our results show that it is acceptable to use polystyrene collection tubes and a carefully chosen stimulant to aid collection, and that samples can be stored at ambient temperature in the field when frozen storage is not available. In addition, they demonstrate the necessity for consistency in sample collection and storage procedures.

The relationship between elastic properties and microstructure of bovine cortical bone.

The relationship between the structure of bone on the microscopic level and its mechanical properties was investigated by comparing bovine cortical bone of two microstructural types. Measurements of elastic properties were made in three orthogonal directions on specimens of plexiform and Haversian bone, taken from the same level of the same bone, using extensional wave ultrasonic techniques. Differences in Young's modulus of elasticity measured in the three directions correspond to observed structural differences; plexiform bone is anisotropic, while Haversian bone appears to be transversely isotropic. The pattern of distribution of the two structural types within different aspects of the same bovine femur suggests that the level of osteonal remodeling is related to the pattern of mechanical stress, especially due to muscular activity, in the bone. This may occur because Haversian remodeling is stimulated by microcracks in regions of high stress and/or repeated stress cycles, thus replacing fatigue-damaged bone and preventing failure.

2,5-Bis(3,4-dimethoxybenzyl)cyclopentylamine, a peripheral dopamine blocking agent.

2,5-Bis(3,4-dimethoxybenzyl)cyclopentylamine hydrochloride has been synthesized. The intermediate 2,5-bis-(3,4-dimethoxybenzyl)cyclopentanone was formed in 91.8% yield using a sodium methoxide catalyzed aldol condensation and catalytic reduction. The oxime of this ketone was catalytically hydrogenated to the amine which was converted to the hydrochloride (76%). The amine hydrochloride was found to be an effective antagonist to the low-dose hypotensive effect of dopamine; the half-life of this effect was 18 min. At dopamine doses of 3 mg/kg in the atropinized and phenoxybenzamine treated dog, the ED50 for blockade was 4--5 mumol/kg. In direct contrast to its peripheral dopamine blocking activity, the compound potentiates apomorphine-induced stereotypy.