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PubMedDate not supplied

Relationship between testosterone serum levels and lifestyle in aging men.

OBJECTIVE: The aim of this study was to evaluate the association between serum levels of testosterone and free testosterone to lifestyle in aging males. METHODS: Men between 45 and 85 years were assessed regarding body mass index (BMI), nicotine and alcohol consumption, stress level, physical and social activity, and sleeping quality by a self-administered questionnaire. In parallel, serum levels of testosterone (T), free testosterone (fT), LH, FSH, DHEA-S, E2 and SHBG were obtained. RESULTS: In total, 375 men with a mean age of 59.9 years (9.2 +/- SD) entered this study; 25.4% and 27.4% had hypogonadal testosterone or free testosterone serum levels, respectively. Nicotine consumption (smokers had higher levels of T and fT; p < 0.01), BMI (negative correlation to T; p < 0.01) and age (negative correlation to fT; p < 0.001) correlated with serum levels of testosterone or free testosterone. Physical and social activity, nicotine and alcohol consumption, stress level and sleep quality did not show a significant association with serum androgen levels. CONCLUSION: This prospective study of 375 men aged 45 to 85 years confirms the correlation between age, BMI and smoking with serum levels of testosterone and free testosterone, whereas the investigated variety of lifestyle factors did not show a significant association to serum androgen levels.

Age Factors↗

PubMed2006

Diagnostic significance of free salivary testosterone measurement using a direct luminescence immunoassay in healthy men and in patients with disorders of androgenic status.

The accurate measurement of testosterone remains a challenge. The determination of the blood testosterone concentrations in serum by conventional immunoassays is inaccurate in men and even more so in females and children. A new luminescence enzyme immunoassay (LIA) has been developed and validated. The high analytical (8.7 pmol/L) and functional (17.3 pmol/L) sensitivity allows the quantification of the very low concentration in saliva, as well as in serum, after 1/40 dilution. This study measured salivary testosterone levels and compared the results with the free levels calculated from total testosterone and sex hormone-binding globulin in eugonadal and hypogonadal men. Salivary testosterone concentrations in healthy men in morning hours were 369 pmol/L (mean), range 263-544 pmol/L, which was statistically significantly higher than that in men with androgen deficiency, 215 pmol/L (mean), range 51-249 pmol/L. Repetitive determination of free testosterone concentrations in saliva (once a week for 5 weeks) showed high stability of results over time, with coefficient of variation 9% (range 5-23%). In this study we showed that free salivary testosterone levels in morning samples correlated well with calculated free testosterone in blood, both in healthy men (R = 0.754, P = 0.001), and in patients with androgen deficiency (R = 0.889, P = 0.0001), though in cases with very low testosterone, salivary concentrations were systematically higher than calculated free testosterone levels in blood.

Adult↗

PubMed2006

Clinical experience with the new long-acting injectable testosterone undecanoate. Report on the educational symposium on the occasion of the 5th World Congress on the Aging Male, 9-12 February 2006, Salzburg, Austria.

This symposium report summarizes first extensive clinical findings with injectable testosterone undecanoate (Nebido) in hypogonadal patients showing clinical symptoms of androgen deficiency with or without erectile dysfunction (ED). This new testosterone formulation (1000 mg testosterone undecanoate in 4 ml castor oil) possesses nearly ideal long-term kinetics, i.e. sustained close mimicking of eugonadal testosterone serum levels without supra- or sub-physiological serum concentrations. The generally accepted administration scheme recommends the second injection 6 weeks after the first one followed by further injections every 12 weeks. Applying this regimen, administration intervals are drastically reduced in comparison to conventional i.m. testosterone preparations (e.g. about 16 injections of testosterone enanthate vs. 4-5 injections of testosterone undecanoate per year). Depending on the testosterone serum levels, individualized therapy is possible by shortening (every 10 weeks) or prolonging (every 14 weeks) the injection intervals. In hypogonadal patients with ED 58% respond to testosterone undecanoate alone. Best results are seen in diabetic hypogonadal patients. The regimen of injectable testosterone undecanoate administration ideally fits recommendations regarding pharmacokinetics, efficacy and safety monitoring.

Aged↗

PubMed2002

Bio-available testosterone levels fall acutely following myocardial infarction in men: association with fibrinolytic factors.

The effect of acute myocardial infarction on plasma levels of testosterone in men is unclear. No previous studies have evaluated the bio-available fraction of testosterone. Low plasma testosterone levels have been associated with several risk factors for myocardial infarction, including an unfavorable fibrinolytic profile. In a prospective, case control study, we examined changes in plasma levels of sex hormones, including bio-available testosterone, in patients with acute myocardial infarction and in control subjects. In addition, changes in hormone levels in patients were compared with alterations in the fibrinolytic profile. Thirty male patients admitted with chest pain were studied. Twenty two had acute myocardial infarction and eight had non-specific chest pain. Plasma levels of total and bio-available testosterone, 17beta-estradiol, sex hormone binding globulin and insulin were measured at baseline and throughout admission. In addition, fibrinolytic factors (plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA) and fibrinogen) were measured in patients who received fibrinolysis. Height and weight, and the subsequent development of heart failure or myocardial dysfunction were also recorded. Patients had lower levels of bio-available testosterone (2.07 +/- 0.75 nmol/L vs. 5.3 +/- 1.7 nmol/L, p < 0.05) and higher levels of 17beta-estradiol (87.9 +/- 39.5 pmol/L vs. 48.1 +/- 18.4 pmol/L, p < 0.001) than controls. Total and bio-available testosterone levels fell acutely following myocardial infarction (11.9 +/- 3.8 nmol/L to 9.7 +/- 3.3 nmol/L, p < 0.05; 1.95 +/- 0.76 nmol/L to 1.55 +/- 0.67 nmol/L, p < 0.05). This reduction was associated with elevation of PAI-I activity and reduction of tPA activity, independent of changes in plasma insulin levels. Patients with lower baseline levels of testosterone and higher levels of 17beta-estradiol had a relatively pro-thrombotic fibrinolytic profile and increased risk of complications. In conclusion, total and bio-available levels of testosterone fall following acute myocardial infarction in men, in association with adverse changes in fibrinolytic profile. It is not clear whether this association represents a direct effect of testosterone on thrombotic tendency but warrants further investigation.

Adult↗

PubMed1999

Detection of nandrolone, testosterone, and their esters in rat and human hair samples.

Nandrolone and testosterone are anabolic androgenic steroids occasionally abused by athletes. A sensitive, specific, and reproducible gas chromatography-mass spectrometry method for the quantitative determination of nandrolone, testosterone, and their esters in hair has been developed. The limits of quantitation of this method, based on 20 mg of hair, were 50 pg/mg for nandrolone and testosterone, 100 pg/mg for testosterone acetate, and 200 pg/mg for nandrolone-decanoate. Nandrolone-d3 and testosterone-d3 were used as internal standards. This method has been applied to the analysis of these compounds incorporated into rat and human hair. Male Long-Evans rats were given nandrolone decanoate 60 mg/kg intraperitoneally (i.p.) once daily for 10 days over a time period of 14 days. Two of the three rats contained nandrolone in the pigmented hair collected at day 21 at a concentration of 63 and 76 pg/mg, respectively. No drug was found in the corresponding nonpigmented hair. The rat hair samples that tested positive for nandrolone contained also nandrolone decanoate in concentrations of 0.9 and 1.2 ng/mg, respectively. In a separate experiment rats were given testosterone acetate 10 mg/kg i.p. once daily for five days. No testosterone or testosterone acetate was detected in the rat hair samples. Hair specimens were also obtained from four self-reported steroid users. The hair of two subjects were determined to be positive for testosterone in concentrations of 54 and 81 pg/mg. These data demonstrate that it is possible to detect the steroids nandrolone, testosterone, and nandrolone decanoate in hair after systemic administration.

Adult↗

PubMed1995

Aberrant hormone balance in fetal autoimmune NZB/W mice following prenatal exposure to testosterone excess or the androgen blocker flutamide.

F1 hybrid New Zealand Black (NZB) x New Zealand White (NZW) (NZB/W) mice are hormone-sensitive models of the human disease systemic lupus erythematosus. In this study, NZB/W fetuses produced by pregnant NZB mice were compared with F1 C57BL/6 x DBA/2 (C57/DBA2) hybrid fetuses produced by nonautoimmune C57BL/6 females. Dams of both strains were treated with testosterone or the androgen blocker flutamide to alter the hormonal environment in late gestation. Hormonal changes in male fetuses carried by treated dams were of interest because hormonal manipulation using either testosterone or flutamide has been shown to increase longevity in male NZB/W offspring. Testosterone-implanted NZB dams developed the expected elevations in circulating maternal testosterone, whereas C57BL/6 dams treated with either testosterone or flutamide had elevated maternal serum testosterone concentrations. The treatment-induced changes in circulating testosterone in NZB dams and C57BL/6 dams were not reflected in serum from 18-day NZB/W or C57/DBA2 fetuses. Male NZB/W offspring from untreated control NZB dams had unexpectedly high levels of serum estradiol and alpha fetoprotein and relatively low extractable testicular testosterone, compared with nonautoimmune male control fetuses. Maternal testosterone treatments produced a significant decrease in serum estradiol in NZB/W male fetuses, and placental testosterone content was also reduced. Our findings suggest that placental androgen control is regulated differently in the autoimmune NZB-NZB/W vs. the nonautoimmune C57BL/6-C57/DBA2 maternal-placental-fetal unit.

Androgen Antagonists↗

PubMed1996

Effect of testosterone on maturational gonadotropin subunit messenger ribonucleic acid levels in the goldfish pituitary.

In this study, we investigated the effects of testosterone and a nonaromatizable androgen, 11 beta-hydroxyandrosterone, on maturational gonadotropin (GtH-II) subunit gene expression in the goldfish pituitary. While testosterone treatment at physiological doses resulted in stimulation of GtH-II-alpha and -beta subunit mRNA production, time-course and dose-response studies performed on sexually immature goldfish of mixed sex, using a wider dose range exceeding physiological levels, demonstrated a biphasic response to in vivo androgen treatment. Time-related treatment with testosterone and 11 beta-hydroxyandrosterone (20 micrograms/fish) resulted in an initial inhibition of GtH-II subunit mRNA production (12-24 h) followed by stimulation at 72-96 h. In dose-response studies, treatment for 24 h with testosterone resulted in a significant stimulation at the low physiological doses of 0.2 and 2 micrograms/fish. At the supraphysiological level of 20 micrograms/fish, testosterone treatment resulted in no stimulation or in decreased GtH-II subunit mRNA levels compared to the control values. Similarly, treatment with 11 beta-hydroxyandrosterone resulted in a significant stimulation of GtH-II subunit mRNA levels at low physiological concentrations (0.2 microgram/ fish) and an inhibition, or no stimulation, at higher concentrations (2-20 micrograms/fish). In sexually mature goldfish of mixed sex, the biphasic effect of testosterone was not observed in vivo, and treatment with this steroid resulted in stimulation of GtH-II subunit mRNA production in a dose-related manner. To investigate the direct action of testosterone, studies were carried out using isolated goldfish pituitary fragments from goldfish of mixed sex in vitro. Treatment with testosterone at various concentrations was found to stimulate GtH-II subunit mRNA production in pituitary glands obtained from both sexually immature and sexually mature goldfish. Overall, the present study demonstrates a stimulatory effect of testosterone on GtH-II subunit mRNA levels in goldfish. The observed stimulation of basal GtH-II subunit mRNA production by testosterone occurs, in part, through a direct action at the level of the pituitary in both sexually immature and mature goldfish.

Androsterone↗

PubMed1998

Imidazoles suppress rat testosterone secretion and testicular interstitial fluid formation In vivo.

The aim of these studies was to examine the effects of imidazoles on testosterone secretion and testicular interstitial fluid (TIF) formation through measurement of serum LH, serum testosterone, TIF testosterone, and TIF volumes. Imidazole, 1-methylimidazole, 4-methylimidazole (4-MI), and ketoconazole, an oral imidazole antifungal agent, caused dose-dependent decreases in testosterone secretion and TIF formation. Imidazole, 2-methylimidazole, and 4-MI decreased LH secretion. 4-MI decreased testosterone secretion 1-6 h after injection, increased testosterone at 8-16 h, decreased LH secretion at 4 h, decreased TIF volumes at 1-8 h, and slightly increased TIF volumes at 24 h. 4-MI blocked the stimulatory effects of hCG on testosterone secretion and prevented an expected increase in LH secretion after the 4-MI-induced decrease in testosterone secretion. 4-MI also reversed the effects of three other stimulants of testosterone secretion that presumably act through three different testicular regulatory systems: N-methyl-D,L-aspartate, an excitatory amino acid; NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor; and naltrexone, an opioid antagonist. These results support the hypothesis that imidazoles inhibit testicular function and male reproductive function through inhibition of testosterone secretion, TIF formation, and LH secretion regulatory systems.

Animals↗

PubMed2000

Testosterone-dependent primer pheromone production in the sebaceous gland of male goat.

To test the hypothesis that the primer pheromone responsible for inducing the "male effect" is produced in the sebaceous gland androgen dependently, we examined the correlation between morphological changes of sebaceous glands and the pheromone activity in skin samples taken from castrated goats that had been treated with testosterone. Five castrated goats were implanted s.c. with testosterone capsules to maintain physiological levels of plasma testosterone for four weeks. Skin samples were obtained from the head region on Day 0 (the day of testosterone implant), Day 7, Day 14, Day 28 (the day of testosterone removal), Day 36, Day 42, and Day 56. Matched blood samples were also collected for measurement of testosterone concentration. The pheromone activity of the ether-extracts of the upper dermal layer containing sebaceous glands was assessed by its stimulatory effect on the hypothalamic GnRH pulse generator, which was monitored for changes of specific multiple unit activity (MUA) in ovariectomized estradiol-primed goats as described previously. The sebaceous gland enlarged during the testosterone treatment but reduced in size after testosterone removal. The pheromone activity first appeared in 2 out of 5 goats on Day 7 and in all the 5 goats by Day 28. Fourteen days after testosterone removal (Day 42), the pheromone activity was no longer detectable in any of the 5 goats. In short, the sebaceous gland size and the pheromone activity shifted almost in parallel. The present results provide strong support for the view that the primer pheromone is produced testosterone dependently in the sebaceous gland of the male goat.

Animals↗

PubMed1999

Functional testosterone receptors in plasma membranes of T cells.

T cells are considered to be unresponsive to testosterone due to the absence of androgen receptors (AR). Here, we demonstrate the testosterone responsiveness of murine splenic T cells in vitro as well as the presence of unconventional cell surface receptors for testosterone and classical intracellular AR. Binding sites for testosterone on the surface of both CD4(+) and CD8(+) subsets of T cells are directly revealed with the impeded ligand testosterone-BSA-FITC by confocal laser scanning microscopy (CLSM) and flow cytometry, respectively. Binding of the plasma membrane impermeable testosterone-BSA conjugate induces a rapid rise (<5 s) in [Ca2+]i of Fura-2-loaded T cells. This rise reflects influx of extracellular Ca2+ through non-voltage-gated and Ni2+-blockable Ca2+ channels of the plasma membrane. The testosterone-BSA-induced Ca2+ import is not affected by cyproterone, a blocker of the AR. In addition, AR are not detectable on the surface of intact T cells when using anti-AR antibodies directed against the amino and carboxy terminus of the AR, although T cells contain AR, as revealed by reverse transcription-polymerase chain reactions and Western blotting. AR can be visualized with the anti-AR antibodies in the cytoplasm of permeabilized T cells by using CLSM, though AR are not detectable in cytosol fractions when using the charcoal binding assay with 3H-R1881 as ligand. Cytoplasmic AR do not translocate to the nucleus of T cells in the presence of testosterone, in contrast to cytoplasmic AR in human cancer LNCaP cells. These findings suggest that the classical AR present in splenic T cells are not active in the genomic pathway. By contrast, the cell surface receptors for testosterone are in a functionally active state, enabling T cells a nongenomic response to testosterone.

Animals↗

PubMed1999

Testosterone and other anabolic steroids as cardiovascular drugs.

There has been much interest in the effect of sex hormones on cardiovascular risk factors and as a therapeutic modality in both men and women. In this article, testosterone is considered as a possible therapy for cardiovascular disease. It has been shown that the level of serum testosterone decreases in men as they age. Healthy men with low testosterone levels have increased cardiovascular risk factors, including high fasting and 2-hour plasma glucose, serum triglycerides, total cholesterol and low-density lipoprotein (LDL) cholesterol, and apo A-I lipoprotein. Injections of testosterone to raise the levels to midnormal range have been shown to decrease total cholesterol and LDL cholesterol, while increasing high-density lipoprotein (HDL) cholesterol. Testosterone affects the clotting system by increasing thromboxane A (2) receptor activity and platelet aggregability. Testosterone has also been shown to augment the fibrinolytic system and antithrombin III activity. In men, testosterone has been shown to have antianginal effects, and endogenous levels have an inverse relationship to systolic blood pressure. Testosterone can be given in oral, injectable, pellet, and transdermal patch forms. There may be a role in administering testosterone to return men to normal physiologic range who have low serum levels. This treatment increases the risk of prostatic cancer, benign prostatism, erythrocytosis, and edema. No long-term studies of the effects of long-term testosterone replacement have been undertaken, so it is difficult to recommend this treatment as yet, but it is being considered as a therapy for augmenting skeletal muscle strength in patients with congestive heart failure.

Anabolic Agents↗

PubMedDate not supplied

Transdermal testosterone therapy improves well-being, mood, and sexual function in premenopausal women.

OBJECTIVE: Circulating testosterone in women declines during the late reproductive years such that otherwise healthy women in their 40s have approximately half the testosterone level as women in their 20s. Despite this, research showing the benefits of androgen replacement has been limited to the postmenopausal years. In view of the known premenopausal physiological decline in testosterone, we have evaluated the efficacy of transdermal testosterone therapy on mood, well-being, and sexual function in eugonadal, premenopausal women presenting with low libido. DESIGN: Premenopausal women with low libido participated in a randomized, placebo-controlled, crossover, efficacy study of testosterone cream (10 mg/day) with two double-blind, 12-week, treatment periods separated by a single-blind, 4-week, washout period. RESULTS: Thirty-four women completed the study per protocol, with 31 women (mean age 39.7 +/- 4.2 years; serum testosterone 1.07 + 0.50 nmol/L) providing complete data. Testosterone therapy resulted in statistically significant improvements in the composite scores of the Psychological General Well-Being Index [+12.9 (95% CI, +4.6 to +21.2), P = 0.003] and the Sabbatsberg Sexual Self-Rating Scale [+15.7 (95% CI, +6.5 to +25.0), P = 0.001] compared with placebo. A mean decrease in the Beck Depression Inventory score approached significance [-2.8 (95% CI, -5.7 to +0.1), P = 0.06]. Mean total testosterone levels during treatment were at the high end of the normal range, and estradiol was unchanged. No adverse effects were reported. CONCLUSIONS: Testosterone therapy improves well-being, mood, and sexual function in premenopausal women with low libido and low testosterone. As a substantial number of women experience diminished sexual interest and well-being during their late reproductive years, further research is warranted to evaluate the benefits and safety of longer-term intervention.

Administration, Cutaneous↗

PubMedDate not supplied

Testosterone aromatization and cognition in women: a randomized, placebo-controlled trial.

OBJECTIVE: To explore whether inhibition of the conversion of testosterone to estradiol modifies the effects of testosterone on cognition in 61 healthy, estrogen-treated postmenopausal women. DESIGN: Seventy-six postmenopausal women using transdermal estrogen for at least 8 weeks, with a serum total testosterone less than 1.2 nmol/L participated in a single-center, double-blind, randomized, placebo-controlled study. All participants received transdermal testosterone, 400 muL of a 0.5% testosterone gel, daily and were randomized to receive either letrozole 2.5 mg/day or an identical placebo tablet. The main outcome measure was cognition, evaluated using a comprehensive battery of standardized neuropsychological tests, at baseline and week 16. RESULTS: Thirty women in each group completed the study. Free testosterone increased from baseline in both groups, with no difference between groups. Free testosterone levels achieved were below the 90th centile for young women in 80% of the participants at week 16. Serum estradiol and sex hormone-binding globulin levels did not differ from baseline or between groups during the study. No clinically significant effects of testosterone treatment were seen for attention and working memory, psychomotor speed, or executive function. Significant improvements were seen for immediate and delayed visual and verbal memory and for simple concentration with testosterone therapy, all of which were unaffected by the aromatase inhibitor. CONCLUSIONS: We did not observe any effects of aromatase inhibition on cognition in healthy, estrogen-treated postmenopausal women treated with testosterone. This may be due to insufficient study power or a true lack of effect. However, our findings highlight that the detection of subtle changes in cognition in well women require the development of sensitive instruments and large randomized, controlled trials.

Administration, Cutaneous↗

PubMed2004

Testosterone versus fluoxetine for depression and fatigue in HIV/AIDS: a placebo-controlled trial.

BACKGROUND: While testosterone's ameliorative effects on depressive disorders and fatigue in HIV-positive patients have been suggested in the literature, no placebo-controlled trial selecting for depressive disorders and including a standard antidepressant has been conducted. Accordingly, this double-blind trial was designed to determine whether testosterone, as well as fluoxetine, is superior to placebo for depression, fatigue, or both. METHOD: One hundred twenty-three men with HIV/AIDS with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition depressive disorder entered the 8-week trial and were randomized to testosterone (up to 400 mg IM testosterone cypionate biweekly), fluoxetine (up to 60 mg/d), or double placebo. Outcome variables were the Clinical Global Impressions Scale for mood and for fatigue, the Hamilton Rating Scale for Depression, and the Chalder Fatigue Scale. RESULTS: Ninety men completed the trial. In intention-to-treat analyses, mood response rates were 54%, 47%, and 44% for fluoxetine, testosterone, and placebo, respectively. Among completers, mood response rates were 70%, 57%, and 53%, respectively; in neither analysis were differences between treatments statistically significant. In contrast, testosterone was superior to fluoxetine and placebo for completers regarding fatigue. In intention-to-treat analysis, response rates were 39%, 56%, and 42% for fluoxetine, testosterone, and placebo, respectively, and for study completers, 41%, 63%, and 52%, respectively, (P < 0.05), CONCLUSION: While over 50% of patients treated with testosterone reported improved mood, this rate was not statistically superior to placebo. Thus, our findings do not support prescription of testosterone as a first-line treatment for depressive disorders in HIV-positive men. However, if validated in additional studies, testosterone may be a useful option for medically ill men experiencing significant fatigue as well as depression.

Acquired Immunodeficiency Syndrome↗

PubMed2003

Transdermal testosterone for women: a new physiological approach for androgen therapy.

Transdermal testosterone patches and topically applied gels have become well accepted for the treatment of testosterone deficiency in men and are currently being developed in appropriate dosage strengths for androgen therapy in women. The furthest developed among these products is an investigational testosterone matrix patch which is now in phase III clinical trials for the treatment of sexual dysfunction in oophorectomized and naturally menopausal women. This review article discusses the biopharmaceutical rationale for the transdermal delivery of testosterone to women, illustrates and quantitatively analyzes the pharmacokinetics and metabolism of the testosterone matrix patch and a recently investigated testosterone gel, and summarizes the efficacy and safety data that have been reported in phase II studies of the testosterone matrix patch in surgically menopausal women with sexual dysfunction and HIV-infected women with the AIDS wasting syndrome. The different effects of oral and transdermal estrogen therapy (ET) on the concentrations of total and free testosterone attained with the testosterone matrix patch are contrasted. Although still in development, transdermal testosterone therapy appears to be a promising new approach for providing physiologically based androgen therapy to women.

Administration, Cutaneous↗

PubMed2006

Testosterone levels among men with spinal cord injury admitted to inpatient rehabilitation.

OBJECTIVE: Although previous research has shown an association between spinal cord injury (SCI) and testosterone production, these studies have yielded inconsistent results. The present study documented the prevalence of low testosterone among men with SCI. DESIGN: Participants were 92 men with SCI participating in inpatient rehabilitation. Data included total serum testosterone level, demographic and injury information, neurologic level and degree of incomplete function, American Spinal Injury Association Impairment Scale grade, and additional laboratory values, including prealbumin, albumin, hematocrit, and aspartate aminotransferase. RESULTS: The median testosterone level for men who sustained injuries <4 mos earlier was 160 ng/dl. Testosterone categories were significantly associated with age, time since injury, hematocrit, albumin level, and aspartate aminotransferase in the univariate analyses. Age, time since injury, and hematocrit levels were significant predictors of low testosterone in the multivariate analysis. CONCLUSION: The prevalence of low testosterone among men with acute SCI seems to be high. The results suggest the need for routine screening for low testosterone among men with SCI and consideration given to testosterone replacement therapy. Future research is needed to investigate the etiology, pathogenesis, and potential avenues for treatment of low testosterone among men with SCI.

Adult↗

PubMed2006

Fathers have lower salivary testosterone levels than unmarried men and married non-fathers in Beijing, China.

A growing body of evidence, almost entirely from North America, has found that male testosterone levels are positively associated with mating effort (male-male competition and mate-seeking behaviour), while lower testosterone levels have been associated with affiliative pair bonding and paternal care. To expand the cross-cultural scope of this research, here we investigate variation in salivary testosterone levels among Chinese men in relation to marital and parenting variables. One hundred and twenty-six men drawn from a Beijing university setting between the ages of 21 and 38 completed a questionnaire and provided both morning and late afternoon saliva samples from which testosterone levels were measured. The 66 unmarried men had slightly higher levels of testosterone than the 30 married non-fathers, but this difference was not statistically significant. However, the 30 fathers exhibited significantly lower testosterone levels than both unmarried men and married non-fathers. Among married non-fathers, marital relationship quality was not significantly related to testosterone levels. Among married fathers, men with children aged less than 4 years of age did not have lower testosterone levels than men with older children. These data are the first outside of North America to show lower testosterone levels among fathers, and lend support to the theoretical view that male testosterone levels differ according to mating and parenting effort.

Adult↗

PubMed1981

Reduced sex hormone binding globulin and derived free testosterone levels in women with severe acne.

Reduced circulating sex hormone binding globulin (SHBG) levels were found in 54% of a group of women with moderate to severe acne and in 60% of another group of twenty-three women who had acne complicated by hirsutism and/or irregular menstrual cycles. The concentrations of SHBG for the women with acne alone (mean 48 +/- 24 nmol/l) and for those with acne and hirsutes (mean 39 +/- 18 nmol/l) were compared with the SHBG concentrations of fifteen unaffected women with normal menstrual cycles (mean 70 +/- 19 nmol/l). The differences in mean SHBG values for both groups of women with acne were significant (P less than 0.001) on comparison with the mean for the unaffected women. Twenty-nine per cent of the women with acne had elevated testosterone values (mean testosterone concentration for the group 1.5 +/- 0.3 nmol/l) and 41% had elevated 'derived' free testosterone levels (mean 21 +/- 6 pmol/l). Of the women with acne and hirsutes 65% had elevated plasma testosterone levels (mean 2.1 +/- 0.6 nmol/l) and 89% had elevated free testosterone concentrations (mean 31 +/- 10 pmol/l). The mean values for testosterone and free testosterone in the plasma of unaffected women (mean testosterone concentration 1.1 +/- 0.3 nmol/l and free testosterone 13 +/- 4 pmol/l) were significantly lower than in women with acne alone (P less than 0.01 and P less than 0.001) and in women with acne and hirsutism (P less than 0.001). This study indicates that a deficiency in SHBG and an elevation in 'derived' free testosterone is a frequent finding in women with severe acne and may be a significant factor in the aetiology and/or perpetuation of this condition.

Acne Vulgaris↗