Sex hormone levels and body hair growth in !Kung San and Kavango men from Namibia

The relation between hair growth and levels of sex hormones in serum and saliva was investigated in 256 !Kung San and Kavango men (ages 18 to 39 years) from Namibia/Southern Africa. Serum concentrations of total testosterone (Tser), 5α-dihydrotestosterone (DHT), and estradiol (E2) as well as the level of bioavailable non-SHBG-bound testosterone in the saliva (Tsal) were determined by radioimmunoassay. The distribution and density of scalp and facial hair as well as the development of terminal hair on the chest, abdomen, pubic area, arms, fingers, and legs were categorized using objective criteria. Covariance analyses revealed marked differences in the distribution of body hair in the San and the Negro sample. This is partly explained by a significant influence of androgen and estrogen levels on the growth of terminal hair. DHT and the ratio DHT/Tser are significantly positively related to midphalangeal hair growth and negatively to pubic hair development. Tsal, the bioavailable fraction of total testosterone, exerts a weak positive influence on the degree of arm and leg hair growth; the most significant positive effect on the growth of abdominal, arm, and leg hair in our samples is caused by E2. The ratio Tser/E2 correlates significantly negatively with the arm and leg hair development and the ratio DHT/E2 with the degree of abdominal, pubic, arm, and leg hair, whereas lower DHT concentrations occur in men with stronger hair development. © 1993 Wiley-Liss, Inc.     

Androgen levels and components of aggressive behavior in men

Serum concentrations of testosterone (Tser), 5 alpha-dihydrotestosterone (DHT), and free testosterone (Tsal) in saliva were determined in 117 healthy young men between the ages of 20 and 30. A battery of standardized tests and projective techniques were administered simultaneously in order to measure various components of aggression, including sexual aggressiveness. All three androgens show reliable positive correlations with self-ratings of spontaneous aggression. Dominance exhibits a positive, statistically significant correlation to Tser and to DHT. In addition, DHT is negatively related to the scale restraint of aggression. These results support previous findings about Tser and point to the importance of other androgens--especially DHT--for this aspect of endocrine-affect relationships. Interest in sexual aggression yielded no significant results for Tser and DHT (Tsal shows a low positive correlation). The ratio DHT/Tser, however, correlates significantly with this component of aggression.     

Sex hormones and stress in the human male

Six blood samples were obtained from each of a group of 33 healthy males between the ages of 19 and 31, following which radioimmunoassays were used to determine the serum concentrations of testosterone (Tser), 5 alpha-dihydrotestosterone (DHT), and estradiol (E2). In addition, the free testosterone (Tsal) was also measured using saliva samples provided by 23 of the subjects. A questionnaire of our own design was administered together with the Sixteen Personality Factor Questionnaire (16 PF-Test) at the time of the first blood sample in order to check the long-term stress loads of our subjects as well as their abilities to deal with stress. During the investigational period, subjects kept daily records of their sleeping and working hours and noted the appearance of stressful situations. Weather data for Hamburg was also included as a variable in this study. A number of significant relationships between sex hormones and stress could be ascertained; however, it should be kept in mind that the correlation coefficients are low and explain only a small percentage of the variance between the variables. The stress variables "weather condition" and the "Q4" factor of the 16 PF-Test are significantly related to E2 (intersubject correlations). For all samples of all subjects, psychic stress correlates positively with the ratio of Tsal/Tser. There is a significant positive intersubject relationship between Tsal and long-term plus concurrent somatic stress, while somatic stressors on the day preceding a blood and saliva sample (acute somatic stress) correlate positively with Tsal and Tser.     

Sex hormone level and body shape of the !Kung San. A contribution to explaining pedomorphic stature of San populations

In order to test the hypothesis that oestrogens as well as androgens modify the body shape resp. the paedomorphous habitus of !Kung San circulating levels of sex hormones (testosterone, 5 alpha-dihydrotestosterone, and oestradiol in the serum as well as free testosterone in the saliva) of 114 healthy !Kung San men from the Northern Kalahari of Namibia were quantitatively determined by means of the radioimmunoassay method. The probands were described by 50 body measurements and morphological characters like gynaecomastia. The results show that sex hormone concentrations and body shape are significantly correlated in !Kung San men as it has been previously demonstrated for non-African samples. This does not only refer to the expression of sexual dimorphism but also to the special aspect of paedomorphism. The hypothesis of Marrett, Davies and Tobias, however, that the paedomorphous type of the San is due to "over-oestrogenization" could not be confirmed. Rather, the comparatively low testosterone level of the !Kung San men seems to be of significance.     

Hormone Specificity, Androgen Metabolism, and Social Behavior

SYNOPSIS. The ability of different sex hormones to activatesocial signals can provide important clues to the biochemicalmechanisms underlying these signals. A pattern of hormone specificityin which testosterone (T) and estradiol (E), but not dihydrotestosterone(DHT), are effective suggests that conversion (aromatization)of T to E in the brain may be involved or required; a patternin which T and DHT, but not E, are effective suggests that conversionof T to DHT may be involved. The hormone specificity of socialsignals in diverse species of vertebrates is reviewed. Aromatizationseems to be of widespread behavioral significance in mammalsandbirds. A role for conversion of T to DHT is suggested forsome signals. Aromatization of T mayalso be important for theactivation of adult female behavior in mammals and lizards,and for the early organization of behavior in mammals and birds.Patterns of hormone specificity differ both across species fora given social signal, and within a given species when differentsignals are compared. An attempt is made to integrate thesefindings by relating patterns of hormone specificity to hormonelevels, steroid receptor and enzyme concentrations and distributions,signal function and dimorphism, and phylogenetic status.     

Paramethasone acetate (PA): corticosteroid potency vs hypothalamic pituitary-gonadal axis

Because paramethasone acetate (PA) suppresses basal and midcycle LH surge and blocks estrogen synthesis in the female, its possible effect upon testicular physiology was evaluated in 13 healthy men by measuring the circulating levels of FSH, LH, prolactin (PRL), testosterone (T), dihydrotestosterone (DHT), androstenedione (A), estradiol (E2) and cortisol (C) every 4 h throughout the day, before (control) and after PA (6 mg/d/7 d). The total concentrations of each hormone, as well as the PA-induced suppressibility (measured as percent decrease in the mean 24 h plasma level) were analyzed. PA suppressed neither the basal nor circadian rhythm of T and had no effect on LH, FSH or PRL output. DHT, A, E2 were significantly reduced and the basal concentrations and circadian variations of C were abolished. PA showed a dual control on the pituitary gonadal axis and while causing a maximal suppressed adrenocortical activity it had no interference in testosterone synthesis.     

Effects of testosterone, dihydrotestosterone and estradiol on gonadotropin release after gonadotropin releasing hormone administration in cyclic mares

Sixteen intact cyclic mares were treated on the fourth day of estrus and then every other day for a total of six injections with 1) testosterone propionate, 2) dihydrotestosterone (DHT) benzoate, 3) estradiol (E2) benzoate or 4) safflower oil. Mares were given gonadotropin releasing hormone (GnRH) on Day 3 of estrus (pretreatment) and again 24 h after the last steroid or oil injection. Treatment with testosterone propionate resulted in a greater (P less than 0.05) follicle-stimulating hormone (FSH) response to the second injection of GnRH compared with all other treatments. Treatment with DHT benzoate also resulted in greater (P less than 0.05) FSH response to GnRH compared with control and E2 benzoate-treated mares. Testosterone propionate and E2 benzoate administration suppressed (P less than 0.05) the normal diestrous rise in FSH concentrations exhibited by the control and DHT benzoate-treated mares. Steroid treatment did not affect the luteinizing hormone (LH) response to GnRH, although testosterone propionate treatment did suppress concentrations of LH in daily blood samples during Days 3 to 6 of treatment. It is concluded that testosterone's effect on FSH after GnRH treatment observed in this and previous experiments can be attributed to two different properties of the hormone or its metabolites acting simultaneously. That is, testosterone increased the secretion of FSH in response to GnRH as did DHT (an androgenic effect). At the same time, testosterone suppressed FSH concentrations in daily blood samples in a manner identical to that of E2 benzoate (an estrogenic effect).     

Salivary hormone concentrations in mothers and fathers becoming parents are not correlated

A time- and date-matched set of saliva samples (N = 229) from nine couples first expecting, and then caring for, their first child were used to test whether hormone changes in the father could be predicted by the hormonal status of the mother. Testosterone, cortisol, and estradiol were quantified from saliva. Neither testosterone nor estradiol concentration was correlated within couples before or after the birth, although there was a positive correlation for cortisol concentration in the mother and father before the birth. As the hormone that might be influenced by chemical signals, that already played a similar role in men and women, and that had been empirically linked to paternal behavior, cortisol concentration was also compared with sex steroid concentrations. The mother's cortisol concentration was positively correlated to the father's testosterone concentration, and the mother's testosterone concentration was positively correlated with the father's cortisol concentration. However, both effects were similar in magnitude to the cortisol to cortisol correlation, and all could parsimoniously be explained by similar responses to a shared environment. Thus, this analysis rejects parallels in peripheral hormone concentrations of estradiol, testosterone, and cortisol in mothers and fathers. However, the available data were not able to test or reject hypotheses about local neuroendocrine homology, nor to control for masking effects of other hormonal demands on men and women, nor to determine the relative importance of shared environment versus mother-father signaling.     

Interpretation of the discrepancy observed between plasma free and salivary testosterone levels in man

The differences observed between plasma free and saliva testosterone levels do not result from methodological artefacts. We postulate that androgens metabolism in salivary glands modulates saliva testosterone levels both in men and women. In women, the "excess" of saliva testosterone (compared to the calculated free testosterone concentration), could be due to conversion of androstenedione in the salivary glands. The rate of this transformation is exaggerated in hirsute patients resulting in a significantly higher excess of saliva testosterone. In men, on the contrary, a "deficit" in saliva testosterone is observed suggesting testosterone transformation in salivary glands. This deficit is more marked in impotent men and appears to be reversed by testosterone administration. Saliva testosterone levels do not merely reflect plasma free hormone concentrations but also afford potentially useful information on androgens metabolism.     

Reexamination of testosterone, dihydrotestosterone, estradiol and estrone levels across the menstrual cycle and in postmenopausal women measured by liquid chromatography-tandem mass spectrometry

Measuring serum androgen levels in women has been challenging due to limitations in method accuracy, precision sensitivity and specificity at low hormone levels. The clinical significance of changes in sex steroids across the menstrual cycle and lifespan has remained controversial, in part due to these limitations. We used validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays to determine testosterone (T) and dihydrotestosterone (DHT) along with estradiol (E2) and estrone (E1) levels across the menstrual cycle of 31 healthy premenopausal females and in 19 postmenopausal females. Samples were obtained in ovulatory women in the early follicular phase (EFP), midcycle and mid luteal phase (MLP). Overall, the levels of T, DHT, E2 and E1 in premenopausal women measured by LC-MS/MS were lower overall than previously reported with immunoassays. In premenopausal women, serum T, free T, E2, E1 and SHBG levels peaked at midcycle and remained higher in the MLP, whereas DHT did not change. In postmenopausal women, T, free T, SHBG and DHT were significantly lower than in premenopausal women, concomitant with declines in E2 and E1. These data support the hypothesis that the changes in T and DHT that occur across the cycle may reflect changes in SHBG and estrogen, whereas in menopause, androgen levels decrease. LC-MS/MS may provide more accurate and precise measurement of sex steroid hormones than prior immunoassay methods and can be useful to assess the clinical significance of changes in T, DHT, E2 and E1 levels in females.     

Multimode sensors as new tools for molecular recognition of testosterone,dihydrotestosterone and estradiol in children's saliva

Increased levels of testosterone (T₂), dihydrotestosterone (DHT) and estradiol (E₂) in children may be responsible for their early/delayed puberty and obesity conditions. Therefore, multimode sensors based on carbon matrices, such as graphite, graphene, fullerene C₆₀ and multiwall carbon nanotubes modified with maltodextrin, were designed to assess reliably T₂, DHT and E₂ in children saliva. The modes used for the assay of hormones were stochastic mode (for qualitative and quantitative determination of hormones) and differential pulse voltammetry mode (for quantitative determination of hormones). The advantage of this type of sensors, for hormone analysis, is their possibility to reach low concentration levels— are placed for children saliva under the detection limit of standard methods (e.g. ELISA used for the determination of these hormones in saliva). This made the multimode sensors an excellent tool for clinical analysis and especially for determination of substances of clinical importance in saliva samples. The proposed method is fast and simple, and no sampling of saliva is required. Copyright © 2014 John Wiley & Sons, Ltd.     

Sex steroid hormones and cognitive functioning in healthy, older men

The precise impact of age-related changes in hormone levels on cognition in men is still unclear due to differing study designs and contradictory findings. This study was undertaken to examine the relationship between endogenous sex hormone levels and cognitive functioning in healthy older men using a comprehensive battery of neuropsychological tests and measurement of serum sex hormone levels. Verbal learning and memory, visual-motor processing, spatial abilities, working memory and attention, and levels of testosterone and estradiol were evaluated in 54 healthy older men. Regression analyses revealed significant curvilinear associations between working memory function and both free and bioavailable testosterone levels, suggesting that an optimal hormone level may exist for maximal performance on tasks of executive/frontal lobe functioning. However, no other relationships were evident between either estradiol or testosterone levels and any of the other cognitive functions evaluated. Hormone assays performed at the end of the study revealed that a considerable portion of the healthy elderly men in our sample met criteria for hypogonadism and suggests that their low hormone levels may have mitigated against discovering other significant hormone-cognition relationships.     

A novel spreadsheet method for calculating the free serum concentrations of testosterone, dihydrotestosterone, estradiol, estrone and cortisol: With illustrative examples from male and female populations

In humans, testosterone (T), dihydrotestosterone (DHT), estradiol (E2), estrone (E1) and cortisol (C) bind to the serum proteins sex hormone-binding globulin (SHBG), albumin (Alb) and corticosteroid-binding globulin (CBG). Equilibrium dialysis is considered to be the “gold standard” for measuring the free concentrations of these steroids but is technically difficult and not widely available. Based on a mathematical model of the 5-ligand/3-protein binding equilibria, we developed a novel spreadsheet method for calculating the free and bioavailable (free + Alb-bound) concentrations of each steroid in terms of the total steroid and protein concentrations. The model uses 15 association constants K_SHBG-X, K_Alb-X, and K_CBG-X (X = T, DHT, E2, E1 and C) that have been estimated from a systematic review of published binding studies. The computation of the free and bioavailable concentrations uses an iterative numerical method that can be readily programmed on a spreadsheet. The method is illustrated with six examples corresponding to young men (YM), old men (OM), obese men (Ob M), young women (YM), pregnant women in the 3rd trimester (Preg T3) and oophorectomized women on oral conjugated equine estrogens (CEE). The resulting free hormone concentrations for YM and YW fall within the normal references ranges obtained by equilibrium dialysis for all five hormones. The model also accounts for the competitive binding effects of high estrogen levels on the free T levels in Preg T3. This novel spreadsheet method provides a “user-friendly” approach for estimating the free concentrations of circulating sex hormones and cortisol in men and women.     

Effects of an 8-week aerobic exercise training on saliva steroid hormones, physical capacity, and quality of life in diabetic obese men

The purpose of the study was to assess the effects of aerobic exercise training on saliva steroid hormones [i.?e., cortisol, dehydroepiandrosterone (DHEA), and testosterone], physical capacity, and quality of life in obese diabetic men. 8 abdominally obese type 2 diabetic men (59.5±1.7 years old, BMI=35.5±1.6?kg/m(2), waist circumference=119.4±3.3?cm) and 9 healthy men (57.4±1.5 years old, BMI=24.5±0.8?kg/m(2), waist circumference=92.3±1.9?cm) participated in the study. The obese diabetic men underwent 8 weeks of aerobic exercise training: twice a week 45?min sessions at 75% of peak heart rate and once a week 45?min session of intermittent exercise. Before and after training, steroid hormone concentrations were analyzed from saliva samples, physical capacity was assessed by the 6-minute walking test, and quality of life was estimated by a specific questionnaire for obese subjects. These data were compared with the data from the healthy untrained men. The basal saliva DHEA and testosterone concentrations, physical capacity, and quality of life scores of the obese diabetic men were significantly lower than those of the healthy men. Aerobic training induces a significant increase in the 6-min walking distance and improve the psychosocial impact dimension of quality of life, without modifying significantly any other parameter investigated. These data suggest that an 8-week aerobic exercise program improves physical capacity and quality of life in obese diabetic men, but was insufficient to correct the anthropometric and hormonal alterations observed in this population.     

Rates of dissociation of sex steroid hormones from human sex hormone-binding globulin: a reassessment

A rapid filtration assay employing dextran-coated charcoal as acceptor particles for free hormone was used to measure the rates of dissociation of dihydrotestosterone (DHT), testosterone (T), and estradiol (E2) from their binding proteins in human serum at 37 degrees C. Because measurements were begun after each hormone had fully (greater than 99%) dissociated from albumin, the observed rates of dissociation correspond to the rates of dissociation of the sex hormone-binding globulin (SHBG)-hormone complexes. The dissociation rate constants of the hormone-SHBG complexes were determined to be 0.016 +/- 0.001, 0.056 +/- 0.002, and 0.083 +/- 0.003 s-1 for DHT, T, and E2, respectively, corresponding to half-times of dissociation (t1/2) of 43, 12 and 8.4 s, respectively. The physiological significance of these findings can best be appreciated by comparing these t1/2 s with the capillary and sinusoidal transit times of various tissues (less than 1 s to approximately 10 s).     

The lower salivary testosterone levels among unmarried and married sexually active men

We examined the influences of regular sexual activity and marital status on salivary testosterone levels in healthy adult Japanese men. Forty-four men (20–66 years) collected their saliva thrice a day (0900–1000, 1300–1400, and 1700–1800). The testosterone levels at each collection time negatively correlated with the ages of the participants; therefore, residual testosterone levels were used for analyses after correcting for age by linear regression. The testosterone-lowering effect of marriage was marginal and the regular sexual activity more strongly associated with lower testosterone levels in morning saliva. The possible neurofeedback systems underlying the phenomenon are discussed.     

Effects of Androgens and Oestrogens on the Behaviour of Chicks in an Imprinting Situation

The behavioural effects of testosterone propionate (TP), 5α-dihydrotestosterone (DHT) and oestradiol benzoate (OB) were investigated in day-old chicks during imprinting sessions to a duck model. TP increased the duration of peeping while inhibiting the following reaction and the twitters. DHT had more or less the same effects while OB induces the reverse behavioural changes. The behavioural effects of hormone injections agree with behavioural sex differences observed in non-injected animals: ♂♂ peep more than ♀♀ which on the other hand produce more twitters. This could be related to sex differences in the hormonal status of the birds at hatching, as it is known that during incubation male chick embryos have higher plasma testosterone levels than ♀♀ of corresponding ages.     

Complex regulation of GH autofeedback under dual-peptide drive: studies under a pharmacological GH and sex steroid clamp

To test the postulate that sex difference, sex steroids, and peptidyl secretagogues control GH autofeedback, 11 healthy postmenopausal women and 14 older men were each given 1) a single iv pulse of GH to enforce negative feedback and 2) continuous iv infusion of saline vs. combined GHRH/GHRP-2 to drive feedback escape during pharmacological estradiol (E(2); women) or testosterone (T; men) supplementation vs. placebo in a double-blind, prospectively randomized crossover design. By three-way ANCOVA, sex difference, sex hormone treatment, peptide stimulation, and placebo/saline responses (covariate) controlled total (integrated) GH recovery during feedback (each P < 0.001). Both sex steroid milieu (P = 0.019) and dual-peptide stimulation (P < 0.001) determined nadir (maximally feedback-suppressed) GH concentrations. E(2)/T exposure elevated nadir GH concentrations during saline infusion (P = 0.003), whereas dual-peptide infusion did so independently of T/E(2) and sex difference (P = 0.001). All three of sex difference (P = 0.001), sex steroid treatment (P = 0.005), and double-peptide stimulation (P < 0.001) augmented recovery of peak (maximally feedback-escaped) GH concentrations. Peak GH responses to dual-peptidyl agonists were greater in women than in men (P = 0.016). E(2)/T augmented peak GH recovery during saline infusion (P < 0.001). Approximate entropy analysis corroborated independent effects of sex steroid treatment (P = 0.012) and peptide infusion (P < 0.001) on GH regularity. In summary, sex difference, sex steroid supplementation, and combined peptide drive influence nadir, peak, and entropic measurements of GH release under controlled negative feedback. To the degree that the pharmacological sex steroid, GH, and dual-peptide clamps provide prephysiological regulatory insights, these outcomes suggest major determinants of pulsatile GH secretion in the feedback domain.     

Contribution of dihydrotestosterone to male sexual behaviour.

OBJECTIVE--To document the relative importance of endogenous sex steroids in modulating the frequency of orgasms, the dominant aspect of sexual behaviour in healthy eugonadal men. DESIGN--Measurement of adrenal and testicular sex steroids in a sample of army recruits and study of their relation to frequency of orgasms ascertained by questionnaire after potential confounding variables were controlled for. SETTING--Military campus and military hospital laboratories in Athens, Greece. SUBJECTS--92 consecutively enrolled healthy male recruits aged 18-22 years. MAIN OUTCOME MEASURES--Weekly number of orgasms. Serum concentrations of testosterone, dehydroepiandrosterone sulphate, dihydrotestosterone, oestradiol, oestrone, delta-4-androstenedione, and sex hormone binding globulin. RESULTS--Serum dihydrotestosterone concentration was the only independent hormonal predictor of the frequency of orgasms; an increase in concentration of 1.36 nmol/l (about 2 SD) corresponded to an average increase of one orgasm a week. CONCLUSIONS--Differences in concentrations of circulating dihydrotestosterone within the normal range may represent a major predictor of sexual activity in healthy young men.