Serum Testosterone Concentrations In Men Research Articles

Testosterone in prevention and treatment of type 2 diabetes in men: Focus on recent randomized controlled trials.

In epidemiological studies, lowered serum testosterone concentrations are common in men with obesity, prediabetes, and established type 2 diabetes (T2D). In men with prediabetes, lowered serum testosterone also predicts a future risk of T2D in men. Administration of testosterone consistently reduces fat mass and increases skeletal muscle mass-body compositional changes expected to be metabolically favorable. In men with established T2D, the effects of testosterone treatment on glycemic measures are inconsistent. Irrespective of baseline serum testosterone concentration in men with prediabetes or newly diagnosed early-onset T2D, testosterone treatment prescribed in conjunction with a lifestyle program has been reported to reduce the risk of T2D by 40% after 2 years, suggesting that either a lifestyle program is required to facilitate the glycemic benefit of testosterone treatment and/or that testosterone treatment has more favorable effects on glycemia in men early in the evolution or onset of the disease. The durability of the benefit and longer-term safety of testosterone treatment have not been established. Therefore, more studies are required before testosterone treatment can be recommended for the prevention and/or treatment of men with or at elevated risk of T2D who do not have hypogonadism due to an established disease of the hypothalamic-pituitary-testicular axis.

Effects of aging and the body mass index on male sex hormones: a cross-sectional study in 701 Brazilian men

Background: Some studies indicated that body mass index (BMI) is inversely proportional to serum testosterone concentrations in men. Purposes: This study aimed to analyze the effects of aging and obesity on total testosterone (TT), free testosterone (FT), bioavailable testosterone (BT), luteinizing hormone (LH), and sex hormone-binding globulin (SHBG) levels. Methods: A cross-sectional study was performed to assess the clinical and laboratory profiles of 701 patients treated at a private urology clinic in Ponta Grossa, Brazil, from January 2016 to December 2018. Results: Patients’ age ranged from 16 to 88 years (mean, 56.9 ± 13.62 years). Age did not significantly influence serum TT concentrations, except compared to patients aged >70 years. However, changes were observed in FT and BT (p < 0.05). The mean SHBG increased with age (p < 0.05). A tendency toward LH elevation was observed in older patients, but it was not statistically significant. An inverse proportional relationship between TT, FT, and BT and the testosterone deficiency rate (TT < 300 ng/dL) was observed within BMI groups (p < 0.05). The testosterone deficiency rate was 21.5% in individuals with normal BMI, 29% in overweight individuals, and 37% in obese individuals. Conclusions: Aging affected the testosterone concentrations in men and became increasingly evident using FT and BT instead of TT. SHBG increased with age. Obesity was associated with a decrease in TT, FT, and BT but also increased the rate of hypogonadism.

The anabolic applications of androgens in older adults with functional limitations.

Aging is associated with a progressive decrease in skeletal muscle mass, strength and power and impairment of physical function. Serum testosterone concentrations in men decrease with advancing age due to defects at all levels of the hypothalamic-pituitary-testicular axis. Testosterone administration increases skeletal muscle mass, strength and power in older men with low or low normal testosterone levels, but the effects on performance-based measures of physical function have been inconsistent. Adequately powered randomized trials are needed to determine the long-term safety and efficacy of testosterone in improving physical function and quality of life in older adults with functional limitations.

Obstructive Sleep Apnea Is Associated With Low Testosterone Levels in Severely Obese Men.

BackgroundDisrupted sleep affects cardio-metabolic and reproductive health. Obstructive sleep apnea syndrome represents a major complication of obesity and has been associated with gonadal axis activity changes and lower serum testosterone concentration in men. However, there is no consistent opinion on the effect of obstructive sleep apnea on testosterone levels in men.ObjectiveThe aim of this study was to determine the influence of obstructive sleep apnea on total and free testosterone levels in severely obese men.Materials and methodsThe study included 104 severely obese (Body Mass Index (BMI) ≥ 35 kg/m2) men, aged 20 to 60, who underwent anthropometric, blood pressure, fasting plasma glucose, lipid profile, and sex hormone measurements. All participants were subjected to polysomnography. According to apnea-hypopnea index (AHI) patients were divided into 3 groups: <15 (n = 20), 15 - 29.9 (n = 17) and ≥ 30 (n = 67).ResultsThere was a significant difference between AHI groups in age (29.1 ± 7.2, 43.2 ± 13.2, 45.2 ± 10.2 years; p < 0.001), BMI (42.8 ± 5.9, 43.2 ± 5.9, 47.1 ± 7.8 kg/m2; p = 0.023), the prevalence of metabolic syndrome (MetS) (55%, 82.4%, 83.6%, p = 0.017), continuous metabolic syndrome score (siMS) (4.01 ± 1.21, 3.42 ± 0.80, 3.94 ± 1.81, 4.20 ± 1.07; p = 0.038), total testosterone (TT) (16.6 ± 6.1, 15.2 ± 5.3, 11.3 ± 4.44 nmol/l; p < 0.001) and free testosterone (FT) levels (440.4 ± 160.8, 389.6 ± 162.5, 294.5 ± 107.0 pmol/l; p < 0.001). TT level was in a significant negative correlation with AHI, oxygen desaturation index (ODI), BMI, MetS and siMS. Also, FT was in a significant negative correlation with AHI, ODI, BMI, age, MetS and siMS. The multiple regression analysis revealed that both AHI and ODI were in significant correlation with TT and FT after adjustment for age, BMI, siMS score and MetS components.ConclusionObstructive sleep apnea is associated with low TT and FT levels in severely obese men.

Obstructive sleep apnea is not an independent determinant of testosterone in men.

Obstructive sleep apnea (OSA) is generally considered to lower serum testosterone concentration in men, although data supporting this as a direct effect are limited. The aim of this study was to determine the relationship between the presence and severity of OSA and testosterone in a community-based cohort of men aged over 40 years. Anthropometry, polysomnography and biomedical information were collected from enrolled, consenting men from the prospective, longitudinal MAILES study cohort. Fasting morning blood samples (n = 1869) were drawn between 2010 and 2012 for measurement of testosterone using liquid chromatography mass spectrometry. Home polysomnography was completed in 861 men between 2010 and 2012. The final analysis sample consisted of 623 men aged 41-86 years. The effect of OSA on testosterone were analyzed using linear regression models controlling for potential confounders (age, BMI and sex hormone binding globulin (SHBG)). The mean (s.d.) cohort characteristics were: age 59.0 (10.2) years, testosterone 16.8 (5.3) nmol/L, SHBG 32.9 (13.1) nmol/L, BMI 28.6 (4.2) kg/m2 and apnoea hypopnoea index (AHI) 14.9 (13.7). OSA was present in 51.5%. There was an inverse relationship between AHI and testosterone (P = 0.01), which was lost after covariate adjustment. These data suggest that obesity, rather than OSA per se, determine testosterone concentration. This accords with the graded effect of weight loss, but limited effect of continuous positive airway pressure to increase testosterone, and highlights the importance of managing obesity in men with low testosterone concentration, particularly in the context of OSA.

Relationship Between Body Mass Index and Serum Testosterone Concentration in Patients Receiving Luteinizing Hormone-releasing Hormone Agonist Therapy for Prostate Cancer

To evaluate the relationship between the body mass index (BMI) and serum testosterone concentrations in men receiving luteinizing hormone-releasing hormone (LHRH) agonist therapy for prostate cancer. A total of 66 white men were included in the present study. All subjects had received LHRH agonist therapy for ≥ 3 months. The BMI was calculated, and the subjects were classified as normal weight (i.e. BMI <25 kg/m(2)), overweight (BMI 25-30 kg/m(2)), or obese (BMI >30 kg/m(2)). The serum testosterone concentration was determined using the highly sensitive isotope dilution-liquid chromatography-tandem mass spectrometry technique. The sex hormone-binding globulin level was determined using an immunometric assay, and the free serum testosterone concentration was calculated. The median serum testosterone concentration of the patients with a BMI <25 kg/m(2) was 5.5 ng/dL. The patients with a BMI of 25-30 kg/m(2) had a median serum testosterone concentration of 3.8 ng/dL. Those patients with a BMI >30 kg/m(2) had a median concentration of 5.7 ng/dL. No significant difference in the serum testosterone concentrations among the 3 groups was found. The sex hormone-binding globulin levels declined with an increasing BMI. The concentration of free testosterone was significantly greater in the obese men. Using an ultrasensitive technique of serum testosterone measurement, the present data have shown that no difference exists in the serum testosterone concentration in the castrate range among normal weight, overweight, and obese patients receiving LHRH agonist therapy for prostate cancer. From our findings and current knowledge, more stringent follow-up or changes in dosage or dosage intervals of LHRH agonist therapy in those with a greater or high BMI is not warranted.

Comparison of serum free testosterone, luteinizing hormone and follicle stimulating hormone levels in diabetics and non-diabetics men- a case-control study.

Diabetic men have been claimed to have lower serum free testosterone (FT) concentrations than non-diabetic men. The aim of this study was to investigate if serum FT, luteinizing hormone (LH), and follicle stimulating hormone (FSH) concentrations are different in patients with type 2 diabetes mellitus compared with healthy men and to identify factors associated with low serum testosterone concentrations in men with type 2 diabetes. Serum FT, LH and FSH concentrations in 65 men with type 2 diabetes between 50 and 55 years compared with 65 non-diabetic men in Valye-Asr Hospital in Birjand, Iran during October 2009 to August 2010. In addition, the relationships between serum FT concentrations with LH and FSH concentrations as well as other factors including age, fast blood sugar and glycemic control (HbA1C) were investigated. Serum FT concentrations were significantly lower in type 2 diabetic patients (2.53±1.68 pg/ml) than in healthy men (4.29±2.43 pg/ml) (P<0.001). There were not any significant differences in LH and FSH concentrations between the two groups. There was a significant negative relationship between serum FT and HbA1C, but this relation for LH and FSH was positive and non-significant (P<0.001). Serum FT concentration is lower in type 2 diabetic patients compared with non-diabetic men suggesting further research to better understand the underlying biologic mechanisms.

Lower Testosterone Levels With Luteinizing Hormone-Releasing Hormone Agonist Therapy Than With Surgical Castration: New Insights Attained by Mass Spectrometry

Androgen deprivation therapy by bilateral orchiectomy (surgical castration) or luteinizing hormone-releasing hormone agonist therapy (medical castration) is recommended for advanced or metastatic prostate cancer. Both methods aim at reducing serum testosterone concentrations to a castrate level which is currently defined as less than 50 ng/dl. The results of previous studies are based on testosterone immunoassays that have insufficient accuracy in the low range. In this study we reevaluated serum testosterone concentrations in men on androgen deprivation therapy using isotope dilution-liquid chromatography-tandem mass spectrometry, an accurate method of measuring testosterone in the castrate range. Subjects underwent surgical castration (34) or received a luteinizing hormone-releasing hormone agonist (32). Serum samples were obtained more than 3 months after surgery or initiation of luteinizing hormone-releasing hormone agonist therapy. Testosterone levels were determined using isotope dilution-liquid chromatography-tandem mass spectrometry. Dihydroepiandrosterone sulfate, androstenedione, sex hormone-binding globulin and inhibin B levels were determined. All subjects had serum testosterone values less than 50 ng/dl and 97% had testosterone concentrations less than 20 ng/dl. Medically castrated men had significantly lower testosterone levels (median 4.0 ng/dl, range less than 2.9 to 20.2) than those surgically castrated (median 9.2 ng/dl, range less than 2.9 to 28.8, p <0.001). No difference was found in dehydroepiandrosterone sulfate, androstenedione and sex hormone-binding globulin levels between the groups, whereas inhibin B levels were significantly higher in the luteinizing hormone-releasing hormone agonist treated group. Using an accurate technique for testosterone measurement, subjects on luteinizing hormone-releasing hormone agonist therapy had significantly lower testosterone concentrations than men who underwent surgical castration. The clinical relevance of these findings remains to be determined.

Genetic determinants of serum testosterone concentrations in men.

Testosterone concentrations in men are associated with cardiovascular morbidity, osteoporosis, and mortality and are affected by age, smoking, and obesity. Because of serum testosterone's high heritability, we performed a meta-analysis of genome-wide association data in 8,938 men from seven cohorts and followed up the genome-wide significant findings in one in silico (n = 871) and two de novo replication cohorts (n = 4,620) to identify genetic loci significantly associated with serum testosterone concentration in men. All these loci were also associated with low serum testosterone concentration defined as <300 ng/dl. Two single-nucleotide polymorphisms at the sex hormone-binding globulin (SHBG) locus (17p13-p12) were identified as independently associated with serum testosterone concentration (rs12150660, p = 1.2×10−41 and rs6258, p = 2.3×10−22). Subjects with ≥3 risk alleles of these variants had 6.5-fold higher risk of having low serum testosterone than subjects with no risk allele. The rs5934505 polymorphism near FAM9B on the X chromosome was also associated with testosterone concentrations (p = 5.6×10−16). The rs6258 polymorphism in exon 4 of SHBG affected SHBG's affinity for binding testosterone and the measured free testosterone fraction (p<0.01). Genetic variants in the SHBG locus and on the X chromosome are associated with a substantial variation in testosterone concentrations and increased risk of low testosterone. rs6258 is the first reported SHBG polymorphism, which affects testosterone binding to SHBG and the free testosterone fraction and could therefore influence the calculation of free testosterone using law-of-mass-action equation.

Association Between Testosterone and Estradiol and Age‐Related Decline in Physical Function in a Diverse Sample of Men

To examine the association between aging and physical function in men by testing a theoretically based model of aging, hormones, body composition, strength, and physical function with data obtained from men enrolled in the Boston Area Community Health/Bone (BACH/Bone) Survey. Cross-sectional, observational survey. Population-based. Eight hundred ten black, Hispanic, and white randomly selected men from the Boston area aged 30 to 79. Testosterone, estradiol, sex hormone-binding globulin, lean and fat mass, grip strength, and summated index of physical function (derived from walk and chair stand tests). Measures of grip strength and physical function declined strongly with age. For instance, 10 years of aging was associated with a 0.49-point difference (scale 0-7) in physical function. Age differences in total testosterone and estradiol concentrations were smaller than age differences in their free fractions. Weak or nonsignificant age-adjusted correlations were observed between hormones and measures of physical function, although path analysis revealed a positive association between testosterone and appendicular lean mass and a strong negative association between testosterone and total fat mass. Lean and fat mass, in turn, were strongly associated with grip strength and physical function, indicating the possibility that testosterone influences physical function via indirect associations with body composition. The age-related decline in serum testosterone concentration in men has a weak association with physical strength and functional outcomes through its associations with lean and fat mass.

Low Serum Testosterone Concentration in Middle-aged Men with Type 2 Diabetes

Low concentrations of endogenous androgens have been linked with insulin resistance and atherosclerosis. Men with diabetes have been reported to have lower serum testosterone concentration than non-diabetic men; however, there has never been a large study. The aim of this study was to investigate if endogenous androgen concentration is certainly lower in a relatively large number of Japanese patients with type 2 diabetes compared with healthy men, and to identify what factors may be associated with low serum testosterone concentrations in men with type 2 diabetes. Serum free testosterone concentrations were measured in 524 healthy men and in 331 consecutive Japanese men with type 2 diabetes between 40 and 69 years old. In addition, we investigated the relationships between serum free testosterone concentration and luteinizing hormone (LH) concentration as well as major cardiovascular risk factors including age, blood pressure, plasma lipid concentration, glycemic control (HbA(1c)), and BMI. Serum free testosterone concentrations were lower in men with type 2 diabetes than in healthy men in the 40-49 years group (10.9 +/- 3.3 vs. 14.0 +/- 3.6 pg/ml, P<0.0001), in the 50-59 years group (10.4 +/- 3.2 vs. 12.1 +/- 2.9 pg/ml, P<0.0001), and in the 60-69 years group (9.5 +/- 2.6 vs. 10.5 +/- 2.9 pg/ml, P = 0.0104). A negative correlation was found between serum free testosterone and LH concentrations (r = -0.326, P<0.0001). In conclusion, serum free testosterone concentration is certainly lower in a relatively large number of Japanese patients with type 2 diabetes compared with healthy men with each decade of life between 40 and 69 years old.

Analytical and physiological factors affecting the interpretation of serum testosterone concentration in men

Most hospital laboratories estimate the concentration of total circulating testosterone using a non-extraction method on an automated multi-channel immunoassay analyser supplied by a small number of multi-national diagnostic companies. Although these platforms offer advantages of quick turnaround times, small volume sampling and random access analysis, proficiency testing schemes suggest the quality of results produced remains similar to that of the early manual radioimmunoassay. An estimate of the bioavailable, non-sex hormone binding globulin (SHBG) bound fraction of circulating testosterone, be that the free or the free plus albumin-bound, may be a better index of gonadal status than total testosterone alone, especially when a borderline hypogonadal level of total testosterone is found, and may avoid misclassification of hypogonadal or eugonadal men. Free or bioavailable testosterone may be calculated or measured. The free androgen index may not give a true reflection of androgen status in men. In the interpretation of serum testosterone concentrations with results >40 nmol/L, the possibility of exogenous administration or abuse needs to be considered. The marked diurnal rhythm in total testosterone should also be taken into account. There may be a diminution of testosterone secretion with advancing age, but the great majority of older men have a circulating total testosterone concentration well within the accepted reference intervals established for younger men. As testosterone concentration may fluctuate markedly both seasonally and from day to day, it may be judicious to measure levels on more than one occasion. Provided that estimates of serum testosterone are unequivocally eugonadal (12.5-40 nmol/L) or hypogonadal (<7.0 nmol/L), results produced by routine automated immunoassays will in all probability give a satisfactory assessment of androgen status in men.Routine biochemical assessment of gonadal function in men should include measurement of early morning luteinizing hormone, follicle stimulating hormone, prolactin and SHBG together with total testosterone, and if necessary some estimate of bioactive testosterone.

Resistance Exercise Does Not Change The Hormonal Response To Subligual Androstenediol Intake

Ingesting androstenediol or androstenedione does not increase serum testosterone concentrations in men, but does elevate serum estradiol concentrations. The elevation in serum estradiol may be exaggerated by resistance exercise. Sublingual administration of androstenediol acutely increases serum testosterone concentrations. However, the effect of resistance exercise on the hormonal response, and the duration of change in serum hormones due to sublingual androstenediol are unknown. PURPOSE This project evaluated the effects of a single session of resistance exercise on the hormonal response to sublingual androstenediol. METHODS Six resistance trained males (22.8 ± 1.0 y, 182.0 ± 3.9 cm, 92.1 ± 2.1 kg, 19.2 ± 3.2% body fat) were administered either sublingual placebo (PL) or 21.4 mg androstenediol (AN) under conditions of a single session of full body resistance exercise consisting of 2 sets of 8–12 repetitions at ∼85% 1-RM (EX) or no exercise (REST). Blood samples were collected before supplementation, at 1, 2, 3, 4, 8, and 12 h post supplementation, with the exercise occurring between h 1 and 2.FigureRESULTS There were no differences in the mass lifted or number of sets or repetitions completed between AN and PL. DISCUSSION These findings indicate that sublingual androstenediol acutely elevates serum testosterone and estradiol concentrations, and that resistance exercise does not alter the increase in serum estradiol or testosterone. These data also indicate that the change in serum hormones due to sublingual androstenediol last less than 8 hours. This project was supported by a Faculty Development Grant from Georgia Southern University.

Effects of prohormone supplementation in humans: a review.

Despite a relative dearth of information on their effects, supplementation with prohormones has become a popular practice. Unlike synthetic anabolic-androgenic steroids, many of these over-the-counter androgens are produced endogenously by adrenal, gonadal and peripheral steroidogenic pathways as part of the normal sexual and reproductive hormonal milieu. It has been contended that peripheral enzymatic conversion of these prohormones to testosterone or nortestosterone (via ingestion of androstenedione/androstenediol or 19-nor-androstenedione/androstenediol, respectively) might lead to anabolic and/or ergogenic effects. Existing data suggest that acute oral ingestion of >or=200 mg androstenedione or androstenediol modestly and transiently increases serum testosterone concentrations in men; however, this is accompanied by greater increases in circulating estrogen(s). At doses < 300 mg/d, oral supplementation for as long as 12-weeks with androstenedione or androstenediol has no effect on body composition or physical performance and decreases high-density lipoprotein cholesterol. Similarly, oral supplementation with norandrostenedione and norandrostenediol for up to eight weeks has no effect on body composition or physical performance. In light of these data, new products have been developed that use alternative modes of prohormone administration (sublingual/transbuccal and cyclodextrin-complexation). Future studies should critically examine the effects of these approaches. However, within the framework of the research reviewed, over-the-counter oral prohormone supplementation is ineffective at increasing muscle mass or athletic performance. As a result of the potential health concerns that have been raised, the risk to benefit ratio of using these substances orally seems unfavorable.

Resistance exercise-induced hormonal responses in men, women, and pubescent boys.

This study was designed to investigate the acute plasma catecholamine (CA) response to resistance exercise and its association with serum testosterone (TES), cortisol (COR), and growth hormone (GH) concentration changes. Six men, six women, and six adolescent boys (14 +/- 0 yr) performed five sets of 10 knee extensions with 40% of one-repetition maximum followed by two sets performed to exhaustion. Arterialized venous blood was sampled before, during, and after the exercise for the hormone analysis. External work performed (Wext), average EMG normalized for maximal EMG, exercise-induced maximal voluntary contraction decline, and plasma volume change (deltaPV) were also determined. No differences between groups were observed in Wext relative to lean body mass, average EMG, or in exercise-induced fatigue. Plasma norepinephrine (NE) concentrations were similar in the three groups. However, peak plasma epinephrine (E) increase from preexercise was about twice as high in boys (5.0 +/- 2.6 nmol.L-1 as in men (2.5 +/- 0.8 nmol.L-1] and in women (2.1 +/- 0.6 nmol.L-1) (P < 0.05). The deltaPV could explain a significant increase in serum TES concentration in men, and increases in GH concentrations in every group, but not that of COR observed only in boys. No correlation between the CA concentration changes and those of the other hormones were observed even if the groups were combined. No associations between the CA and the other hormone responses were observed. However, the results may suggest a trend for higher stress response to this particular exercise in the boys than in adults.

Serum testosterone concentrations in men with alcoholic cirrhosis: Background for variation

Median serum testosterone concentration of men with alcoholic cirrhosis (n = 216) did not differ significantly from normal controls (n = 51), but serum testosterone concentrations varied by a factor 43.9 in patients compared to 3.2 in controls ( P < .001). Nineteen percent of the patients had serum testosterone concentrations above 30 nmol/L. Serum concentrations of sex-hormone-binding globulin (SHBG) were significantly ( P < .001) raised, and serum concentrations of calculated nonprotein-bound and non-SHBG-bound testosterone were significantly ( P < .001) decreased in patients compared to normal control values. A number of background variables were analyzed with reference to serum testosterone concentrations by means of multiple regression techniques after having divided the patients into groups (A, B, C) with decreasing liver function by a modification of the Child-Turcotte's criteria. The only significant ( P < .01) background variables associated with log serum testosterone concentrations were: group C (β = −0.828), group B (β = −0.222), age (years) (β = −0.012), duration of hospitalization (days) (β = −0.0077), and concentration of SHBG (nmol/L) (β = 0.0044). Neither previous nor recent (within last six months) alcohol consumption influenced serum testosterone concentrations significantly, but about 50% of the patients had abstained from ethanol for two months or more. The same background variables as above were included as significantly ( P < .01) associated with log serum concentrations of calculated nonprotein-bound testosterone and calculated non-SHBG-bound testosterone, except that SHBG was insignificantly associated to any of the two proportions and that testicular volume was significantly ( P < .05) associated with log non-SHBG bound testosterone. Our data indicate that serum testosterone concentrations (total and nonbound) decreased significantly with decreasing liver function in men with alcoholic cirrhosis.

Effects of alpha-methyldopa on male sexual function

To determine the frequency and possible mechanism whereby alpha-methyldopa causes disturbances in male sexuality, 105 hypertensive men using this drug were interviewed; serum testosterone was measured in those with diminished sexual functioning (N=36) and a subgroup of subjects with no such alterations (N=30). The occurrence of impotence (N=28) was dose-dependent, with frequencies of 14.3%, 23.4%, and 52.2% in men taking <1.0 g/day, 1.0–1.5 g/day, and ≥2.0 g/day of alpha-methyldopa, respectively. Serum testosterone concentrations in men using alpha-methyldopa who had impotence (606±23 ng/100 ml, mean±S.E.M.), depressed libido (601±21 ng/100 ml), and normal potency (591±18 ng/100 ml) were similar to healthy adult non-hypertensive males of the same age (624±26 ng/100 ml). Health-care professionals should query all hypertensive patients about sexual symptoms before and during drug therapy, since these are a common potential cause of non-compliance.

Suppression of serum testosterone concentrations in men by an oral contraceptive preparation.

The suppression of serum testosterone levels in 5 normal men by an oral contraceptive (Eugynon 50 50 mcg ethinylestradiol plus 500 mcg norgestrel) is reported. The volunteers aged 21-39 took 1 tablet each day for 9 days. Testosterone levels measured by radioimmunoassay fell rapidly for the 1st 4 days and then continued to fall at a slower rate. On the 9th day the levels had fallen to 8% of the initial levels (.36 ng/ml). Following discontinuation of the drug the levels recovered fully within a week. All men experienced loss of libido during the latter 1/2 of the ingestion period. It is suggested that norgestrel alone or combined with small doses of ethinylestradiol warrants a trial in treating prostatic cancer.