Concentrations Of Epitestosterone Research Articles

Impact of hormonal contraceptives on urinary steroid profile in relation to serum hormone changes and CYP17A1 polymorphism.

To detect doping with endogenous steroids, six urinary steroids are longitudinally monitored in the athlete biological passport (ABP). These steroids include testosterone, etiocholanolone, androsterone, 5α-androstane-3α,17β-diol, 5β-androstane-3α,17β-diol, and the testosterone isomer epitestosterone. It is known that the intake of hormonal contraceptives may interfere with the ABP biomarkers. A previous study showed that athletes using hormonal contraceptives (HCs) display lower urinary epitestosterone concentrations than non-using athletes. In this study, we analyzed the urinary steroid profile prior to and three months after administration of an oral HC including levonorgestrel and ethinylestradiol (n=55). The urinary concentrations of all the ABP metabolites decreased after threemonths, with epitestosterone showing the largest decline (median 6.78 to 3.04ng/mL, p˂0.0001) followed by 5α-androstane-3α,17β-diol (median 23.5 to 12.83ng/mL, p˂0.0001), and testosterone (median 5.32 to 3.66, p˂0.0001). Epitestosterone is included in two of the five ratios in the ABP (T/E and 5αAdiol/E), and consequently these ratios increased 1.7-fold (range 0.27 to 8.50) and 1.26-fold (range 0.14 to 5.91), respectively. Some of these changes may mimic the changes seen after administration of endogenous steroids leading to atypical findings. Notably, even though participants used the same contraceptive treatment schedule, the HC-mediated epitestosterone change varied to a large extent (median 0.43-fold, range 0.06 to 6.5) and were associated with a functional T˃C promoter polymorphism in CYP17A1. Moreover, the epitestosterone changes correlated with HC-induced testosterone and gonadotropins changes in serum, indicating that urinary epitestosterone reflects the androgen load in HC-using women.

Development of a Derivatization Method for Investigating Testosterone and Dehydroepiandrosterone Using Tandem Mass Spectrometry in Saliva Samples from Young Professional Soccer Players Pre- and Post-Training

In the last decade, high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) combined with electrospray ionization (ESI) has been widely used for determining low concentrations of steroids, and derivatization has often been employed to enhance detection. In the present study, endogenous steroids were extracted using a Strata-XL polymeric reverse phase cartridge. The isolated steroids were reacted with 2-hydrazino-1- methylpyridine (HMP) at 50 °C for 30 min. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used in a positive mode with multiple reaction monitoring (MRM) for the quantification of testosterone (T) and its precursor, dehydroepiandrosterone (DHEA), in saliva samples collected from twenty young Saudi professional soccer players. The analytes were separated on an ACE Ultracore 2.5 Superphenylhexyl column (150 × 3.0 mm id). The extraction recovery during the pre-treatment was >89% and gave <±20% for inter- and intra-assay precision and accuracy. The limits of quantification (LOQ) were found to be 20 pg/mL for (T and DHEA) and 50 pg/mL for Epitestosterone (EPI). The results showed no significant variation in the concentration of T between pre and post training, whereas DHEA was significantly increased after short-term exercise. These results could indicate that there is no correlation between T and its precursor DHEA level following short term physical activity. EPI concentrations could not be detected with a LOQ of 50 pg/mL in the saliva samples.

Urinary steroid profile in females - the impact of menstrual cycle and emergency contraceptives.

Today's doping tests involving longitudinal monitoring of steroid profiles are difficult in women. Women have more complex hormonal fluctuations than men and commonly take drugs such as hormonal contraceptives that are shown to affect biomarkers used in these doping tests. In this study, we followed six women's urinary steroid profile during one menstrual cycle, including both glucuronides and sulfate conjugated fractions. Additionally, we studied what happens to the steroidal module of the Athlete Biological Passport (ABP) after administration of an emergency contraceptive (levonorgestrel, NorLevo®). The study shows that there are large individual variations in all metabolites included in the ABP and that the administration of emergency contraceptives may lead to suspicious steroid profile findings in the ABP. Urinary epitestosterone concentration increased during the menstrual cycle, leading to a decrease in the testosterone/epitestosterone ratio. The ratios followed in the ABP varied widely throughout the menstrual cycle, the coefficient of variation (CV) ranging from 4 to 99%. There was a 3-fold decrease in epitestosterone 24 h post administration of the emergency contraceptive pill and androsterone, etiocholanolone, and 5β- androstan-3α,17β-diol concentrations decreased about 2-fold. When analyzed with the ABP software, one of the six women had an atypical profile after taking the emergency contraceptive. Furthermore, we could not find any alterations in excretion routes (i.e., if the metabolites are excreted as glucuronide or sulfate conjugates) during the menstrual cycle or after administration of emergency contraceptive, indicating no direct effect on phase II enzymes. Copyright © 2016 John Wiley & Sons, Ltd.

Discordant genotyping results using DNA isolated from anti-doping control urine samples.

The UGT2B17 gene deletion polymorphism is known to correlate to urinary concentration of testosterone-glucuronide and hence this genotype exerts a large impact on the testosterone/epitestosterone (T/E) ratio, a biomarker for testosterone doping. The objective of this study was to assess if DNA isolated from athletes' urine samples (n = 713) obtained in routine doping controls could be targeted for genotyping analysis for future integration in the athlete's passport. A control population (n = 21) including both urine and blood DNA was used for genotyping concordance test. Another aim was to study a large group (n = 596) of authentic elite athletes in respect of urinary steroid profile in relation to genetic variation. First we found that the genotype results when using urine-derived DNA did not correlate sufficiently with the genotype obtained from whole blood DNA. Secondly we found males with one or two UGT2B17 alleles had higher T/E (mean 1.63 ± 0.93) than females (mean 1.28 ± 1.08), p˂0.001. Unexpectedly, we found that several male del/del athletes in power sports had a T/E ˃1. If men in power sport exert a different urinary steroid profile needs to be further investigated. The other polymorphisms investigated in the CYP17A1, UGT2B7 and UGT2B15 genes did not show any associations with testosterone and epitestosterone concentrations. Our results show that genotyping using urine samples according to our method is not useful in an anti-doping setting. Instead, it is of importance for the anti-doping test programs to include baseline values in the ABP to minimize any putative impact of genotype. Copyright © 2016 John Wiley & Sons, Ltd.

The impact of genetics and hormonal contraceptives on the steroid profile in female athletes.

The steroid module of the Athlete Biological Passport, the newest innovation in doping testing, is currently being finalized for implementation. Several factors, other than doping, can affect the longitudinal steroid profile. In this study, we investigated the effect of hormonal contraceptives (HC) as well as the effect of three polymorphisms on female steroid profiles in relation to doping controls. The study population consisted of 79 female elite athletes between the ages of 18 and 45. HC were used by 32% of the subjects. A full urinary steroid profile was obtained using World Anti-Doping Agency accredited methods. In addition all subjects were genotyped for copy number variation of UGT2B17 and SNPs in UGT2B7 and CYP17. Subjects using HC excreted 40% less epitestosterone as compared to non-users (p = 0.005) but showed no difference in testosterone excretion. When removing individuals homozygous for the deletion in UGT2B17, the testosterone to epitestosterone (T/E) ratio was 29% higher in the HC group (p = 0.016). In agreement with previous findings in men, copy number variation of UGT2B17 had significant effect on female urinary testosterone excretion and therefore also the T/E ratio. Subjects homozygous for the T allele of CYP17 showed a lower urinary epitestosterone concentration than the other CYP17 genotypes. It is of great importance that the athlete’s steroidal passport can compensate for all possible normal variability in steroid profiles from women. Therefore, considering the large impact of HC on female steroid profiles, we suggest that the use of HC should be a mandatory question on the doping control form.

LC-MS/MS-Based Assay for Free and Deconjugated Testosterone and Epitestosterone in Rat Urine and Serum

Testosterone and epitestosterone are mainly excreted as glucuronides. The aim of this study was to develop and validate a method using liquid chromatography tandem mass spectrometry (LC-MS/MS) to analyse testosterone and epitestosterone in rat serum and urine to assist in vivo studies on steroid metabolism. The method was developed by spiking charcoal stripped rat plasma and urine with the analytes. The developed method was then applied to serum (n=6) and urine samples (n=6) from young male brown Norway rats to determine testosterone and epitestosterone concentrations. The assay showed linearity within quantification range coefficient (r2) values above 0.991. Optimum conditions were determined for the deconjugation of glucuronidated testosterone and epitestosterone along with the internal standard stanozolol D3. Accuracy, precision and extraction recovery for both compounds was satisfactory in both matrices. The method was capable of quantifying 0.250 ng/mL concentrations of testosterone and epitestosterone in 100 μL of serum and urine. The average concentrations of free and deconjugated testosterone and epitestosterone found in the rat samples were: urine–201.68 ± 90.16 ng/mL and 85.37 ± 21.20 ng/mL; serum– 363.40 ± 11.615 ng/mL and 1.75 ± 0.118 ng/mL, respectively. This method is sensitive, specific and reproducible for the determination of free and deconjugated testosterone and epitestosterone in rat serum and urine. The method can be used for in vivo analysis for further investigations of testosterone and epitestosterone concentrations in studies monitoring endocrine dysfunctions and doping.

Abnormal Plasma Neuroactive Progestagen Derivatives in Ill, Neonatal Foals Presented to the Neonatal Intensive Care Unit

AimsTo determine the pregnane profile of foals with neonatal maladjustment syndrome (NMS) and compare it with that of healthy controls and sick, non‐NMS foals.MethodsThirty‐two foals with a clinical diagnosis of NMS, 12 foals with other neonatal disorders and 10 healthy control foals were selected for the study. Heparinised blood samples were collected from each group of foals and pregnane and androgen concentrations were determined using liquid chromatography mass spectrometry at 0, 24 and 48 h of age.ResultsHealthy foals showed a significant decrease in pregnane concentrations over the first 48 h of life (P<0.01). Foals with NMS and sick, non‐NMS foals had significantly increased progesterone, pregnenolone, androstenedione dehydroepiandrosterone and epitestosterone concentrations compared with healthy foals (P<0.05). Progesterone and pregnenolone concentrations of sick, non‐NMS foals decreased significantly over 48 h (P<0.05), whereas concentrations in NMS foals remained elevated.Conclusions and practical relevancePregnane concentrations of ill, neonatal foals remain elevated following birth, reflective of a delayed, or interrupted, transition from intra‐ to extra‐uterine life. These pregnanes are potent allosteric modulators of the GABAA receptor and are important in providing tonic inhibition of fetal central nervous system activity and damping movement to prevent maternal damage. Infusion of the pregnane allopregnanolone into neonatal foals leads to somnolence and loss of affinity for the dam (Madigan et al. ). Together, these findings suggest that the pathogenesis of NMS may be associated with the persistence of high concentrations of pregnanes. Serial progesterone and pregnenolone measurement may be useful in aiding diagnosis of NMS.Ethical animal researchThe UC Davis IACUC approved the project. Sources of funding: Private donation. Competing interests: None.

Abnormal plasma neuroactive progestagen derivatives in ill, neonatal foals presented to the neonatal intensive care unit

Increased levels of pregnanes have been reported in foals with neonatal maladjustment syndrome (NMS). These steroids may cross the blood-brain barrier and have depressive effects in the central nervous system leading to behavioural abnormalities and altered states of consciousness in affected foals. The aim of this study was to determine the pregnane profile of foals with NMS and compare it with that of healthy controls and sick, non-NMS foals. Prospective-clinical study. Thirty-two foals with a clinical diagnosis of NMS, 12 foals with other neonatal disorders and 10 healthy control foals were selected for the study. Heparinised blood samples were collected from each group of foals and pregnane and androgen concentrations determined using liquid chromatography mass spectrometry at 0, 24 and 48 h of age. Healthy foals showed a significant decrease in pregnane concentrations over the first 48 h of life (P<0.01). Foals with NMS and sick, non-NMS foals had significantly increased progesterone, pregnenolone, androstenedione, dehydroepiandrosterone and epitestosterone concentrations compared with healthy foals (P<0.05). Progesterone and pregnenolone concentrations of sick, non-NMS foals decreased significantly over 48 h (P<0.05), whereas concentrations in NMS foals remained increased. Pregnane concentrations of ill, neonatal foals remain increased following birth, reflecting a delayed, or interrupted, transition from intra- to extra-uterine life. Serial progesterone and pregnenolone measurement may be useful in aiding diagnosis of NMS.

Urine Steroid Profile of Judo Competitors Affected by Acute Physical Exercises

A heterogeneous group of 10 male and 15 female judo players are utilized in this study. The subjects complete a standardized maximal treadmill exercise test. Urine samples are collected at the pre- and postexercise stages. The urine steroids are measured using a gas chromatography-mass spectrometry instrument. In rest and after exercise, significantly higher testosterone and epitestosterone concentrations in males (p < 0.01) are found. The etiocholanolone-dehydroepiandrosterone (DHEA) ratio is significantly lower in males than females (p < 0.05). In both males and females, etiocholanolone concentration significantly decreases with the effect of exercise (p < 0.05). 11-OH etiocholanolone concentration also significantly decreases, but only in females (p < 0.05). Positive correlation is found between the changes of the etiocholanolone and epitestosterone concentration caused by exercise.

Urinary Analysis of Four Testosterone Metabolites and Pregnanediol by Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry after Oral Administrations of Testosterone

The most frequently used method to demonstrate testosterone abuse is the determination of the testosterone and epitestosterone concentration ratio (T/E ratio) in urine. Nevertheless, it is known that factors other than testosterone administration may increase the T/E ratio. In the last years, the determination of the carbon isotope ratio has proven to be the most promising method to help discriminate between naturally elevated T/E ratios and those reflecting T use. In this paper, an excretion study following oral administration of 40 mg testosterone undecanoate initially and 13 h later is presented. Four testosterone metabolites (androsterone, etiocholanolone, 5 alpha-androstanediol, and 5 beta-androstanediol) together with an endogenous reference (5 beta-pregnanediol) were extracted from the urines and the delta(13)C/(12)C ratio of each compound was analyzed by gas chromatography-combustion-isotope ratio mass spectrometry. The results show similar maximum delta(13)C-value variations (parts per thousand difference of delta(13)C/(12)C ratio from the isotope ratio standard) for the T metabolites and concomitant changes of the T/E ratios after administration of the first and the second dose of T. Whereas the T/E ratios as well as the androsterone, etiocholanolone and 5 alpha-androstanediol delta(13)C-values returned to the baseline 15 h after the second T administration, a decrease of the 5 beta-androstanediol delta-values could be detected for over 40 h. This suggests that measurements of 5 beta-androstanediol delta-values allow the detection of a testosterone ingestion over a longer post-administration period than other T metabolites delta(13)C-values or than the usual T/E ratio approach.

Sex- and age-related changes in epitestosterone in relation to pregnenolone sulfate and testosterone in normal subjects.

Epitestosterone has been demonstrated to act at various levels as a weak antiandrogen. So far, its serum levels have been followed up only in males. Epitestosterone and its major circulating precursor pregnenolone sulfate and T were measured in serum from 211 healthy women and 386 men to find out whether serum concentrations of epitestosterone are sufficient to exert its antiandrogenic actions. In women, epitestosterone exhibited a maximum around 20 yr of age, followed by a continuous decline up to menopause and by a further increase in the postmenopause. In men, maximum epitestosterone levels were detected at around 35 yr of age, followed by a continuous decrease. Pregnenolone sulfate levels in women reached their maximum at about age 32 yr and then declined continuously, and in males the maximum was reached about 5 yr earlier and then remained nearly constant. Epitestosterone correlated with pregnenolone sulfate only in males. In both sexes a sharp decrease of the epitestosterone/T ratio around puberty occurred. In conclusion, concentrations of epitestosterone and pregnenolone sulfate are age dependent and, at least in prepubertal boys and girls, epitestosterone reaches or even exceeds the concentrations of T, thus supporting its role as an endogenous antiandrogen. The dissimilarities in the course of epitestosterone levels through the lifespan of men and women and its relation to pregnenolone sulfate concentrations raise the question of the contribution of the adrenals and gonads to the production of both steroids and even to the uniformity of the mechanism of epitestosterone formation.

Detection of Epitestosterone Doping by Isotope Ratio Mass Spectrometry

Epitestosterone is prohibited by sport authorities because its administration will lower the urinary testosterone/epitestosterone ratio, a marker of testosterone administration. A definitive method for detecting epitestosterone administration is needed. We developed a gas chromatography-combustion-isotope ratio mass spectrometry method for measuring the delta(13)C values for urinary epitestosterone. Sample preparation included deconjugation with beta-glucuronidase, solid-phase extraction, and semipreparative HPLC. Epitestosterone concentrations were determined by gas chromatography-mass spectrometry for urines obtained from a control group of 456 healthy males. Epitestosterone delta(13)C values were determined for 43 control urines with epitestosterone concentrations > or =40 microg/L (139 nmol/L) and 10 athletes' urines with epitestosterone concentrations > or =180 microg/L (624 nmol/L), respectively. The log epitestosterone concentration distribution was gaussian [mean, 3.30; SD, 0.706; geometric mean, 27.0 microg/L (93.6 nmol/L)]. The delta(13)C values for four synthetic epitestosterones were low (less than or equal to -30.3 per thousand) and differed significantly (P <0.0001). The SDs of between-assay precision studies were low (< or =0.73 per thousand). The mean delta(13)C values for urine samples obtained from 43 healthy males was -23.8 per thousand (SD, 0.93 per thousand). Nine of 10 athletes' urine samples with epitestosterone concentrations >180 microg/L (624 nmol/L) had delta(13)C values within +/- 3 SD of the control group. The delta(13)C value of epitestosterone in one sample was -32.6 per thousand (z-score, 9.4), suggesting that epitestosterone was administered. In addition, the likelihood of simultaneous testosterone administration was supported by low delta(13)C values for androsterone and etiocholanolone. Determining delta(13)C values for urinary epitestosterone is useful for detecting cases of epitestosterone administration because the mean delta(13)C values for a control group is high (-23.8 per thousand) compared with the delta(13)C values for synthetic epitestosterones.

The Effect of Epitestosterone on Estrogen Biosynthesisin Vitro

The concentrations of epitestosterone in human serum correlates negatively with that of estradiol. The possible explanation of this relation was addressed, and the influence of epitestosterone on kinetics of estradiol formation in vitro was evaluated. The concentration of epitestosterone was measured in serum of 54 men participating in a screening program for prostate disease. Epitestosterone inhibition of aromatase and 17beta-hydroxysteroid dehydrogenase activities was tested in vitro in the system consisting of human placental microsomes, NADPH or NAD and NADP respectively, and epitestosterone in increasing concentrations. Testosterone, androstenedione, estrone and 17beta-estradiol were utilized as substrates. A significant negative correlation between epitestosterone and estradiol levels in human male serum was found. No inhibition of aromatase activity was observed; however, inhibition of 17beta-hydroxysteroid dehydrogenase was found preferentially in the direction leading to oxidation of the C-17 hydroxy group. The inhibitory effect of epitestosterone was more pronounced with androgens as substrates. Epitestosterone could influence the formation of estradiol in vitro rather by inhibition of 17beta-hydroxysteroid dehydrogenase than by blocking aromatase activity.

Adrenal and gonadal contributions to urinary excretion and plasma concentration of epitestosterone in men--effect of adrenal stimulation and implications for detection of testosterone abuse.

The ratio of urinary testosterone (T) to epitestosterone (EpiT) is used to detect T abuse in sport. Also, plasma or urinary concentrations of EpiT have been measured to assess testicular steroidogenesis during hormonal male contraception. Further investigations are required to evaluate the relative contributions of the testis and adrenal to EpiT production. To this purpose, we have compared basal urinary EpiT glucuronide and plasma EpiT and the response to synthetic adrenocorticotrophic hormone (ACTH) stimulation between eugonadal and hypogonadal men. The basal urinary excretion rate of EpiT glucuronide was determined in 34 eugonadal men. Six men, clinically diagnosed as hypogonadal, and 6 out of the 34 eugonadal men previously described, received an intramuscular injection of synthetic ACTH depot (1 mg) at 0800 h on two consecutive days. Blood samples were collected prior to and then at 1.5, 8, 24, 25.5, 32 and 48 h with respect to the first administration (0 h). 24-h urine specimens were collected from 0800 h on days 1 and 2 (baseline) and 3 and 4 (stimulation). Plasma EpiT, T and cortisol were measured by RIA and urinary EpiT and T, following glucuronide hydrolysis, by gas chromatography-mass spectrometry (extract combines aglycones with a minor amount of urinary free steroids). Basal excretion rates of EpiT glucuronide in eugonadal men (range: 62-751 nmol/24 h) were considerably greater than in hypogonadal men (range: 3-34 nmol/24 h). Mean basal plasma EpiT in eugonadal men (1.32 +/- 0.08 nmol/l) were greater than in hypogonadal men (0.68 +/- 0.04 nmol/l). In each group, synthetic ACTH stimulation increased plasma cortisol 4-fold. In eugonadal men, plasma and urinary EpiT were unchanged whereas plasma and urinary T glucuronide decreased in response to ACTH. In hypogonadal patients, ACTH increased plasma and urinary EpiT while plasma T remained unchanged. The testes are the major source of epitestosterone, the adrenal contribution being relatively modest. Following adrenal stimulation, urinary epitestosterone glucuronide increases considerably in hypogonadal men but this increase is masked in eugonadal men because testicular production is probably suppressed by the ACTH-induced rise in cortisol. Activation of the adrenal cortex results in no change or only a small decrease in the urinary T/EpiT ratio in eugonadal men.

Epitestosterone in human blood and prostatic tissue.

Epitestosterone, a C19-steroid with anti-androgenic activity, was determined in the plasma of 234 boys and men from the ages of 6-86 years, and in the prostate tissue of 15 men 55-82 years of age. It was documented that, while in adulthood the concentration of epitestosterone is about ten times lower than the concentration of testosterone, in the pre-pubertal period the level of epitestosterone is similar or even higher than that of testosterone. In the hyperplastic prostate tissue the content of epitestosterone is comparable to that of androstenedione, it is about twice as high as the content of testosterone and approximately half that of the content of dihydrotestosterone. At least in the case of pre-pubertal boys and in the prostatic tissue it is therefore possible to include epitestosterone into consideration as a regulatory factor for the androgen-dependent events.

Plasma levels of epitestosterone from prepuberty to adult life

Epitestosterone has for a long time been considered as a biologically inactive steroid. However, recently a distinct antiandrogenic activity of this naturally occurring endogenous epimer of testosterone has been demonstrated. Epitestosterone plays a role in the control of doping with testosterone, since an arbitrary ratio of testosterone to epitestosterone in urine has been accepted as a marker for testosterone abuse. For this reason, its urinary excretion has been examined intensively by several authors. On the other hand, its concentration in the blood of men was reported only randomly in a few cases. In the present study the epitestosterone level in human plasma was determined by a specific radioimmunoassay and the concentration of epitestosterone was established in age groups of males of 6 to 65 years of age. There is a clear age dependence of epitestosterone plasma concentration in males. In young boys before puberty, antiandrogenic epitestosterone prevails over testosterone, in adults a striking decline of the ratio epitestosterone: testosterone can be observed.

Epitestosterone and oestrogen concentration in plasma of cows during induction of parturition with prostaglandin F 2α

Administration of 25 mg Dinoprost (PGF 2α-THAM) to six cows on day 270 of gestation induced parturition in five animals within 48–72 h. Six other cows served as controls. Blood samples were collected from the jugular vein three times a day and the concentrations of epitestosterone, unconjugated oestrogens (ether extractable) and conjugated oestrogens (not ether extractable) were measured by radioimmunoassay. Epitestosterone and conjugated oestrogen levels were similar to those of the control group (5–7 and 11–24 nmol/l respectively). After parturition, the concentration decreased to basal levels. The concentration of unconjugated oestrogens reached maximum levels at birth but the absolute values were lower in the group with induced parturition (2.8 ± 0.7 nmol/l) compared to the control group (9.2±1.0 nmol/l).

Identification of epitestosterone in the plasma and testis of the lizard Tiliqua (Trachydosaurus) rugosa

Blood and testicular extracts of the scincid lizard Tiliqua (Trachydosaurus) rugosa were analyzed using thin-layer, column, and high-performance liquid chromatography. The major androgens isolated were epitestosterone, testosterone, and androstenedione. Epitestosterone was characterized by chromatography in several systems, and by derivative formation. Epitestosterone was further identified in testicular extracts by gas chromatography-mass spectrometry. Immunoreactive material was detected in tissue extracts using an antiserum specific to epitestosterone. The maximum concentration of epitestosterone in blood, measured by radioimmunoassay, was four times that of testosterone (approximately 900 and 200 nmol/l, respectively). Epitestosterone could not be detected in the blood of intact females and the concentration of this steroid was low in castrate males. The maximum testicular concentrations (pmol/testis) were 390 (nonincubated) and 2050 (incubated) for epitestosterone, and 2025 (nonincubated) and 1040 (incubated) for testosterone. Both plasma and testicular concentrations showed considerable seasonal variation. The identification of endogenous epitestosterone confirms the results of earlier investigations using radioactive substrates. The occurrence of this steroid as a major product of the testis in T. rugosa is discussed in relation to androgens in reptiles and other vertebrates.

Stimulation of androgen and oestrogen concentrations in plasma of cows after administration of a synthetic glucocorticoid (flumethasone) at the end of gestation.

Administration of flumethasone (3.5 mg i.m.) to six cows on day 260 of pregnancy induced parturition in only one animal. In the other five cows circulating concentrations of epitestosterone and conjugated oestrogens increased to reach maximum values (epitestosterone, 13.73 +/- 2.81 nmol/l; conjugated oestrogens, 33.59 +/- 6.87 nmol/l) 2-3 days after treatment. Concentrations of these steroids were raised as long as the synthetic glucocorticoid was present in the circulation (as judged by depression of cortisol concentrations). After clearance of the drug, concentrations of these steroids declined to values present in the control group. Concentrations of unconjugated oestrogens were only slightly raised after flumethasone. In contrast to the effect observed after administration on day 260, treatment on day 270 induced parturition in four of six treated animals. In these cows, mean circulating concentrations of epitestosterone, unconjugated and conjugated oestrogens increased to 9.50 +/- 2.96, 9.62 +/- 1.48 and 36.51 +/- 4.8 nmol/l respectively to reach concentrations observed in the control group at parturition. After parturition the concentrations of epitestosterone and oestrogens declined rapidly in all groups.

Epitestosterone in the plasma of the goat during pregnancy and at parturition.

Epitestosterone, a product of the metabolism of androstenedione by the caprine placenta in vitro, is present in the plasma of the pregnant goat. The maternal concentrations of both epitestosterone and unconjugated oestrogens (mostly oestradiol-17 alpha) in the blood increased before parturition and dropped post partum. Measurement of arteriovenous differences at term indicated that epitestosterone was secreted by the uterus; its production was not dependent on the presence of corpora lutea. It is suggested that the concentration of epitestosterone (+ androstenedione + oestrogens) in maternal plasma may be used as an indicator of placental C-17,20 lyase activity; the slight rise in the concentration of these compounds prepartum suggests a relatively small increase in flow through this enzyme.