Serum Concentrations Of Dihydrotestosterone Research Articles

Age-related decrease in serum dihydrotestosterone concentration is accompanied by impaired vascular status

IntroductionThe effect of androgens on the cardiovascular system in humans is ambiguous. Moreover, still little is known about the effects of the most potent androgen, dihydrotestosterone, on arterial stiffness and endothelial function. The aim of this study was to evaluate whether age-dependent alterations in serum concentration of dihydrotestosterone and its circulating metabolite are accompanied by changes in endothelial function and arterial stiffness. MethodsIn 12 young and 11 older men, basal serum concentrations of testosterone, dehydroepiandrosterone sulfate (DHAE-S), androstenedione (AE), dihydrotestosterone (DHT) and androstanediol glucuronide (ADG) were analyzed in relation to vascular status including cIMT — carotid intima media thickness, cAI — central augmentation index, crPWV — carotid radial pulse wave velocity, SI — stiffness index, endothelial and inflammatory markers. ResultsAlthough concentration of testosterone was not different between young and older group, it was demonstrated that DHT, DHEA-S, AE and ADG were significantly lower in older men in comparison to young men (p < 0.01). Interestingly the most surprising difference was found for DHT concentration, that was as much as 61 % lower in aged men that displayed significantly higher values of cIMT, AI, crPWV and SI (p < 10−4), suggestive of arterial stiffness. Furthermore, DHT was negatively correlated to all arterial wall parameters (cAI, crPWV, SI and cIMT), c-reactive protein (CRP) and hyaluronic acid (HA) concentration, as well as positively correlated to markers of endothelial function (MNA and 6-keto-PGF1α) in all studied individuals (n = 23). ConclusionsWe have shown that ageing leads to a significant decrease in DHT concentration that is accompanied by impaired arterial wall characteristics and worsened endothelial function. Therefore more attention should be paid to the DHT, DHEA-S and ADG concentrations as a biomarkers for vascular dysfunction in ageing men.

Serum concentrations of dihydrotestosterone are associated with symptoms of hypogonadism in biochemically eugonadal men

PurposeSymptoms of hypogonadism are often reported by subjects with normal serum testosterone (T) levels. We aimed to assess the association between clinical symptoms in andrological outpatients and sex steroids levels.MethodsThis is a retrospective cross-sectional cohort study in an Academic clinic and research unit. International Index of Erectile Function (IIEF, EF domain) and Aging Males Symptoms scale (AMS) questionnaires were completed by 635 and 574 men, respectively (mean age: 47.3 ± 13.9 and 47.4 ± 13.8 years, p = 0.829), free of interfering medications with complaints possibly related to hypogonadism.ResultsSerum total/free T as well as dihydro-T (DHT) was associated with IIEF-EF and AMS scores in the overall population using univariate analyses. Multivariate approaches revealed DHT concentrations in subjects with normal T levels (n = 416, Total T > 12 nmol/L) to be significant predictors of AMS scores. A 0.1 nmol/l serum DHT increase within the eugonadal range was associated with a 4.67% decrease in odds of having worse symptoms (p = 0.011). In men with biochemical hypogonadism (Total T < 12 nmol/L), total and free T rather than DHT were associated with AMS results. This association was not found for IIEF-EF scores. Indirect effects of age and BMI were seen for relations with hormone concentrations but not questionnaire scores.ConclusionDHT can be associated with symptoms of hypogonadism in biochemically eugonadal men. Serum DHT measurement might be helpful once the diagnosis of hypogonadism has been ruled out but should not be routinely included in the primary diagnostic process.

The effect of finasteride in men with benign prostatic hyperplasia

Background. Benign prostatic hyperplasia is a progressive, androgen-dependent disease resulting in enlargement of the prostate gland and urinary obstruction. Preventing the conversion of testosterone to its tissue-active form, dihydrotestosterone, by inhibiting the enzyme 5α-reductase could decrease the action of androgens in their target tissues; in the prostate the result might be a decrease in prostatic hyperplasia and therefore in symptoms of urinary obstruction. Methods. In a double-blind study, we evaluated the effect of two doses offinasteride (1 mg and 5 mg) and placebo, each given once daily for 12 months, in 895 men with prostatic hyperplasia. Urinary symptoms, urinary flow, prostatic volume, and serum concentrations of dihydrotestosterone and prostate-specific antigen were determined periodically during the treatment period. Results. As compared with the men in the placebo group, the men treated with 5 mg of finasteride per day had a significant decrease in total urinary-symptom scores (P <0.001), an increase of 1.6 ml per second (22 percent, P <0.001) in the maximal urinary-flow rate, and a 19 percent decrease in prostatic volume (P <0.001). The men treated with 1 mg of finasteride per day did not have a significant decrease in total urinary-symptom scores, but had an increase of 1.4 ml per second (23 percent) in the maximal urinary-flow rate, and an 18 percent decrease in prostatic volume. The men given placebo had no changes in total urinary-symptom scores, an increase of 0.2 ml per second (8 percent) in the maximal urinary-flow rate, and a 3 percent decrease in prostatic volume. The frequency of adverse effects in the three groups was similar, except for a higher incidence of decreased libido, impotence, and ejaculatory disorders in the finasteride-treated groups. Conclusions. The treatment of benign prostatic hyperplasia with 5 mg of finasteride per day results in a significant decrease in symptoms of obstruction, an increase in urinary flow, and a decrease in prostatic volume, but at a slightly increased risk of sexual dysfunction.

Influence of age and photoperiod on steroidogenic function of the testis in the golden hamster.

The golden (Syrian) hamster is a seasonal breeder, and exposure of adult animals to short days results in severe gonadal regression with morphological features that resemble the immature testis. The purpose of this study was to investigate testicular steroidogenic capacity in the golden hamster and to analyse the influence of age and photoperiod on this process. Hamsters aged 36 days were maintained on a long photoperiod (14L:10D), and adult animals were then exposed to a long or a short photoperiod (6L:18D) for 14 weeks (the period of time required to achieve maximal gonadal regression), to assess circulating levels and in vitro production of testosterone, dihydrotestosterone and androstane-3 alpha, 17 beta-diol. In peripubertal hamsters, androstane-3 alpha, 17 beta-diol was the main circulating androgen detected, whereas in active adult animals, testosterone showed the highest serum levels. In hamsters exposed to a short photoperiod, blood testosterone levels were significantly lower than levels in adult hamsters exposed to a long photoperiod. Exposure of adult hamsters to a short photoperiod produced a marked reduction in serum concentrations of dihydrotestosterone and androstane-3 alpha, 17 beta-diol, which was not accompanied by a decrease in testicular 5 alpha-reductase activity. In the in vitro experiments, active adult testes were less sensitive than inactive adult testes to stimulation of androgen production with hCG, but showed similar sensitivity to the gonads from hamsters aged 36 days. In accordance with circulating androgen concentrations, the principal androgens produced in the in vitro assays from peripubertal and normal adult testes were androstane-3 alpha, 17 beta-diol and testosterone, respectively. Unexpectedly, the main androgen produced from regressed testes under in vitro conditions was androstane-3 alpha, 17 beta-diol. Inactive gonads released more androstane-3 alpha, 17 beta-diol than did normal adult testes and total in vitro androgen production (testosterone + dihydrotestosterone + androstane-3 alpha, 17 beta-diol) from adult testes was not diminished by exposure to a short photoperiod. However, in spite of the significant increase detected in production of androstane-3 alpha, 17 beta-diol in vitro from regressed testes, inactive gonads produced less androstane-3 alpha, 17 beta-diol than did peripubertal testes. In summary, our studies suggest that testicular androgen biosynthetic capacity in adult hamsters exposed to short photoperiod is not reduced and these regressed testes represent an intermediate physiological state between peripubertal and active adult testes. The significant decrease detected in serum androgen concentrations during the involution phase could result from the absence of stimulating pituitary factors, together with a negative regulation of steroidogenesis by different non-steroidal signals originating within and/or outside of the testis.

Effect of finasteride on serum concentrations of dihydrotestosterone and testosterone in three clinically normal sexually intact adult male dogs

Abstract Objective To determine the effect of finasteride at dosages of 0.10, 0.25, and 0.50 mg/kg of body weight, PO, q 24 h, on serum concentrations of dihydrotestosterone (DHT) and testosterone (T) in clinically normal sexually intact adult male dogs. Animals 3 intact adult male dogs less than 5 years old. Procedure Concentrations of DHT and T were measured by radioimmunoassay of serum from dogs randomly assigned to 1 of 3 treatment groups (0.10, 0.25, or 0.50 mg of finasteride/kg, PO, q 24 h, for 7 days) in a Latin square design with repeated measures. Blood was obtained before and on days 1, 2, 4, and 7 of treatment; 3 blood samples were obtained at 20 minute intervals to detect pulsatile secretion of DHT and T. Dogs were untreated at least 2 weeks between treatments. Results Finasteride at all doses was associated with a mean decrease in concentration of DHT of 55% (range, 155 ± 32.3 pg/ml to 70 ± 15 pg/ml), but had no effect on concentration of T (before treatment, 2.6 ± 0.38 ng/ml; after treatment, 2.2 ± 0.63 ng/ml). Conclusions Finasteride at these doses significantly decreased serum concentration of DHT in sexually intact adult male dogs. Concentrations of DHT and T before and 7 days after treatment did not differ by dosage of finasteride administered. Clinical Relevance Finasteride (5 mg; 1 tablet) may be a drug of choice for treatment of benign prostatic hypertrophy in 10- to 50-kg dogs. (Am J Vet Res 1998;59:762-764)

Benign and Malignant Neoplasms of the Prostate

AbstractBackground. Benign prostatic hyperplasia is a progressive, androgen-dependent disease resulting in enlargement of the prostate gland and urinary obstruction. Preventing the conversion of testosterone to its tissue-active form, dihydrotestosterone, by inhibiting the enzyme 5α-reductase could decrease the action of androgens in their target tissues; in the prostate the result might be a decrease in prostatic hyperplasia and therefore in symptoms of urinary obstruction.Methods. In a double-blind study, we evaluated the effect of two doses offinasteride (1 mg and 5 mg) and placebo, each given once daily for 12 months, in 895 men with prostatic hyperplasia. Urinary symptoms, urinary flow, prostatic volume, and serum concentrations of dihydrotestosterone and prostate-specific antigen were determined periodically during the treatment period.Results. As compared with the men in the placebo group, the men treated with 5 mg of finasteride per day had a significant decrease in total urinary-symptom scores (P...

Seasonality in Endocrine and Exocrine Testicular Function of the Adult Rhesus Monkey (Macaca mulatta) Maintained in a Controlled Laboratory Environment

Testicular exocrine and endocrine function was monitored in adult male rhesus monkeys maintained for up to 4 years in a controlled environment isolated from seasonal changes in light, humidity and temperature and from female animals. Marked circannual variations were found in both functions. Spermatogenesis and exocrine function were maximal in the autumn and winter months as indicated by histological studies and the measurement of testicular volume, frequency of spontaneous and provoked ejaculations and in sperm output. The serum level and metabolic clearance rate and production rate of testosterone were also maximal during this period as were the serum concentrations of dihydrotestosterone, cortisol and biologically active luteinizing hormone. By contrast the serum prolactin and dehydroepiandrosterone levels showed an inverse pattern, achieving their highest levels in spring, during the period of reduced testicular function. Since such marked circannual variations in testicular and pituitary functions persist in monkeys isolated from external environmental influences, the existence of an inherent regulatory mechanism can be postulated. Such distinct variations in testicular function must be taken into consideration when using the male rhesus monkey as an experimental model for human reproductive function.