Sex Steroid Concentrations Research Articles

The pattern of female genital hormonal disease in juvenile myoclonic epilepsy

Objective: to reveal and investigate hormonal characteristics in women of childbearing age in juvenile myoclonic epilepsy (JME). Patients and methods. The concentrations of sex steroid and tropic hormones were analyzed in 48 women of childbearing age who suffered from JME and received monotherapy or bitherapy with antiepileptic drugs (AEDs) for more than a year. For comparison of their values, a control group included 15 healthy women who did not take AEDs. Results and discussion. 66.7% of the patients were found to have ovarian hormonal dysfunction characterized by a significant increase in the level of luteinizing hormone and testosterone in the follicular phase of the cycle and a decrease in that of progesterone in the luteal phase compared with the control group. The hormonal deviations were influenced by disease duration and age-related onset in JME. Generalized tonicclonic seizures concurrent with myoclonic ones, bitherapy, and disease onset before menarche and in the period of the menstrual cycle favored the development of hormonal deviations to a greater extent than myoclonic seizures only, monotherapy, and disease onset after the establishment of the cycle. Valproates were most commonly used in the therapy of JME; however, there were no significant differences in the hormonal deficiencies when different chemical groups of AEDs were administered.

Obesity Biomarkers, Metabolism and Risk of Cancer: An Epidemiological Perspective.

Obesity is associated with metabolic alterations that may pose a biological link between body fatness and risk of cancer. Elucidating the role of obesity-related biomarkers in cancer development is essential for developing targeted strategies aiming at obesity-associated cancer prevention. Molecular epidemiological studies of the past decades have provided evidence that major hormonal pathways linking obesity and cancer risk include the insulin and insulin-like growth factor-1 (IGF-1) axis, sex-steroid hormones, adipokines and chronic low-grade inflammation. These pathways are interrelated with each other, and their importance varies by obesity-related cancer type. The insulin/IGF-1 axis has been implicated to play an important mediating role in the association between obesity and risk of pancreatic, colorectal and prostate cancer. Endogenous sex-steroid hormone concentrations, in particular obesity-associated pre-diagnostic elevations of estrogens and androgens, play an important role in postmenopausal breast cancer and endometrial cancer development. The adipokines adiponectin and leptin and adipocyte-mediated chronic low-grade inflammation represented by the acute-phase C-reactive protein may explain a substantial part of the association between obesity and risk of colorectal cancer. There is less evidence on whether these hormonal pathways play a mediating role in other obesity-associated types of cancer. In this chapter, the molecular epidemiologic evidence from prospective studies relating circulating obesity-related biomarkers to cancer risk is summarized, taking into account available evidence from Mendelian Randomization investigations aiming at improving causal inference.

Cloning and pattern of gsdf mRNA during gonadal development in the protogynous Epinephelus akaara

Gonadal soma-derived factor (gsdf) is a teleost- and gonad-specific growth factor involved in early germ cell development. The red spotted grouper, Epinephelus akaara, as a protogynous hermaphrodite, provides a novel model for understanding the mechanisms of sex determination and differentiation in teleosts. In the present study, a 2307-bp long gsdf gene was cloned from E. akaara and there was further analysis of its tissue distribution and gonadal patterns of gene expression during the female phase and sex change developmental stages. The cellular localization of gsdf at the late transitional developmental stage was also analyzed. In addition, the concentrations of serum sex steroid hormones (E2, 11-KT and DHP) were determined. The gsdf transcripts were exclusively localized in the gonad. During the female phase at an early developmental stage, when the ovotestis contained mainly oogonia and primary growth oocytes, the gsdf mRNA was relatively more abundant. The relative abundance of gsdf decreased, however, and the lesser amount was sustained with the advancement of oocyte development. During the transitional phase, the relative abundance of gsdf mRNA increased slightly at the early developmental stage and there were further increases in relative abundance in the late developmental stage, and the gsdf transcripts were observed in the Sertoli cells surrounding early developing spermatogonia. Among the sex steroids, 11-KT concentrations were positively correlated with amount of gsdf mRNA during sex change. These results suggest that gsdf could have roles in regulating pre-meiotic germ cell proliferation and be involved in sex change in E. akaara.

Responses of sex steroid hormones to different intensities of exercise in endurance athletes.

Previous studies have shown that acute exercise elevates sex steroid hormone concentrations in rodents and that sprint exercise increases circulating testosterone in healthy young men. However, the effect of different exercise intensities on sex steroid hormone responses at different levels of physical fitness is still unclear. In this study, we compared circulating sex steroid hormone responses at different exercise intensities in athletes and non-athletes. Eight male endurance athletes and 11 non-athletes performed two 15 min sessions of submaximal exercise at 40 and 70% peak oxygen uptake (V̇(O2peak)), respectively, and exercised at 90% V̇(O2peak) until exhaustion. Venous blood samples were collected during the last minute of each submaximal exercise session and immediately after exhaustion. Acute exercise at 40, 70 and 90% V̇(O2peak) induced significant increases in serum dehydroepiandrosterone (DHEA) and free testosterone concentrations in non-athletes. On the contrary, only 90% V̇O2 peak exercise led to an increase in serum DHEA and free testosterone concentrations in athletes. Serum 5α-dihydrotestosterone concentrations increased with 90% V̇(O2peak) exercise in both athletes and non-athletes. Additionally, serum estradiol concentrations were significantly increased at moderate and high exercise intensities in both athletes and non-athletes. These results indicate that in endurance athletes, serum sex steroid hormone concentrations, especially serum DHEA and 5α-dihydrotestosterone concentrations, increased only with high-intensity exercise, suggesting that different responses of sex steroid hormone secretion are induced by different exercise intensities in individuals with low and high levels of physical fitness. In athletes, therefore, high-intensity exercise may be required to increase circulating sex steroid hormone concentrations.

Early puberty of farmed tambaqui (Colossoma macropomum): Possible influence of male sexual maturation on harvest weight

Tambaqui is the main native fresh water fish in Brazilian aquaculture. Despite the increasing production of tambaqui (annual growth of approximately 8%), no study has addressed the effects of farming on tambaqui's reproductive physiology and growth performance. As part of an institutional portfolio that aims to increase the production of tambaqui per area of cultivation, the present work details the tambaqui's gametogenesis and steroidogenesis during 10months of farming, until they reached the market size. Spermatogenesis is very precocious (750g fish) and apparently is a rapid and constant process in tambaqui testes, with major concentration of mature fish in August. On the other hand, oogenesis is a much longer process that starts only in fish at around 1200g and does not complete before harvesting (no mature female observed). The plasmatic concentration of sex steroids is very similar among immature male and female tambaqui. However, testosterone and estradiol rise in parallel with testis development while only the second rises with ovarian primary growth. Concentration of 17α-hydroxyprogesterone remains at basal levels during spermatogenesis of farmed tambaqui, but it slightly increases during oocyte primary growth. At harvest, the biometrical analysis reveals that female and male tambaqui yield different gutted weight in the order of 16% in favor of the former. Most probably due to the precocious gonad maturation that farmed males go through (5m old), females are heavier at harvest (12m old) and therefore stand out as the most profitable gender to be produced in the tambaqui farming industry.

Basic reproductive biology of daggertooth pike conger, Muraenesox cinereus: A possible model for oogenesis in Anguilliformes.

IntroductionEels are animals commonly used in zoological research, as these species have a unique catadromous life history and belong to a phylogenetically ancient group of Teleostei. However, eel reproduction is difficult to investigate, since mature samples are not easily obtainable in the wild. In this study, we tested daggertooth pike conger (Muraenesox cinereus), an Anguilliformes species, as a potential model for the investigation of the reproductive biology of eels. Seventy individuals were caught between June and October, which is supposed to be their spawning season, from inshore of the Seto Inland Sea.ResultsThe lengths and ages of samples ranged from 510 to 1239 mm and three to nine years, respectively, and the sex ratio was skewed towards females (96 % of the total sample). The gonado-somatic index of the females peaked in July. Histological observation revealed that these ovaries were similar to those of other eel species and contained matured oocytes (migratory-nucleus stage), suggesting that pike conger spawn inshore in July. The plasma concentrations of sex steroid hormones (estradiol-17β and 11-keto-testosterone) in females gradually increased during maturation and decreased after spawning, indicating the involvement of these hormones in oogenesis of pike conger.ConclusionsThe present study is the first to report on characteristics of natural oogenesis in pike conger. Because naturally maturing samples can easily be captured, daggertooth pike conger may represent an excellent model for the study of reproduction in Anguilliformes.

Sex- and seasonally related changes in plasma gonadotropins and sex steroids concentration in the European beaver (Castor fiber)

The European beaver (Castor fiber) is the largest free-living rodent in Eurasia which belongs to the group of long-day breeders. A seasonally changing photoperiod may be related to cyclic changes in the secretion of gonadotropins and sex steroids. The goal of our study was to determine sex- and seasonally dependent changes in the concentration of gonadotropins (LH—luteinizing hormone and FSH—follicle-stimulating hormone) and steroids (T—testosterone, E2—estradiol, and P4—progesterone) in the blood plasma of free-living male and female beavers. Blood samples were collected in April—pregnancy in females; July—the end of lactation, raising of offspring; and November—sexual silence. Our results indicate that in females, a higher FSH concentration was noted in July and November than in April. Plasma T content did not differ between males and females, but in females, it was higher in April as compared with July or November. Plasma P4 concentration was the highest in females in April. In summary, our findings indicate, for the first time, that in the European beaver occur sex- and/or seasonally related changes in the concentration of plasma FSH and sex steroids (T and P4). Seasonal differences in the tested hormones can be associated with the differential activity of the hypothalamo-pituitary-gonadal axis during various reproductive stages of the beaver.

Male Sex is Associated with a Reduced Alveolar Epithelial Sodium Transport.

Respiratory distress syndrome (RDS) is the most frequent pulmonary complication in preterm infants. RDS incidence differs between genders, which has been called the male disadvantage. Besides maturation of the surfactant system, Na+ transport driven alveolar fluid clearance is crucial for the prevention of RDS. Na+ transport is mediated by the epithelial Na+ channel (ENaC) and the Na,K-ATPase, therefore potential differences in their expression or activity possibly contribute to the gender imbalance observed in RDS. Fetal distal lung epithelial (FDLE) cells of rat fetuses were separated by sex and analyzed regarding expression and activity of the Na+ transporters. Ussing chamber experiments showed a higher baseline short-circuit current (ISC) and amiloride-sensitive ΔISC in FDLE cells of female origin. In addition, maximal amiloride-sensitive ΔISC and maximal ouabain-sensitive ΔISC of female cells were higher when measured in the presence of a permeabilized basolateral or apical membrane, respectively. The number of FDLE cells per fetus recoverable during cell isolation was also significantly higher in females. In addition, lung wet-to-dry weight ratio was lower in fetal and newborn female pups. Female derived FDLE cells had higher mRNA levels of the ENaC- and Na,K-ATPase subunits. Furthermore, estrogen (ER) and progesterone receptor (PR) mRNA levels were higher in female cells, which might render female cells more responsive, while concentrations of placenta-derived sex steroids do not differ between both genders during fetal life. Inhibition of ER-β abolished the sex differences in Na+ transport and female cells were more responsive to estradiol stimulation. In conclusion, a higher alveolar Na+ transport, possibly attributable to a higher expression of hormone receptors in female FDLE cells, provides an explanation for the well known sex-related difference in RDS occurrence and outcome.

Testicular fine-needle aspiration for the assessment of intratesticular hormone concentrations.

Measurement of intratesticular sex steroid concentrations in men informs both the development of male hormonal contraceptives and the understanding of male infertility. Given the challenges of using invasive techniques to measure testicular hormone physiology, our group has used a minimally-invasive fine-needle aspiration technique to measure intratesticular hormones in normal healthy men. Herein, we present a post-hoc analysis of the safety and efficacy of testicular fine-needle aspiration (FNA) completed as part of six clinical trials. From 2001 through 2011, a total of 404 procedures were conducted among 163 research volunteers, 85.9% of which were successful in obtaining sufficient fluid for the measurement of intratesticular steroid concentrations. Pain was the most common side effect, with 36.8% of procedures associated with moderate procedural pain and 4.7% with severe procedural pain. Postprocedural pain was uncommon and abated within a few days. Mild local bruising occurred with 14.9% of procedures. Two serious adverse events (0.5%) required surgical intervention. The risk of an adverse event was not associated with age, body mass index, testicular size, or the volume of fluid aspirated. Testicular FNA to obtain fluid for measurement of intratesticular steroid concentrations frequently causes mild to moderate procedural pain, but serious adverse events occur rarely. Testicular FNA has been instrumental for defining human intratesticular hormone physiology and is a minimally-invasive, safe, effective method for obtaining fluid for research on testicular physiology and pathology.

Investigating factors contributing to reduced embryo survival in farm‐raised Atlantic salmon, Salmo salar L.

Embryo mortality of Atlantic salmon, Salmo salar, has been increasing for more than a decade in the State of Maine, a leading producer of this species in the United States. Increasing embryo mortality not only creates a financial bottleneck for farms but also prevents the sale of surplus eggs as an additional source of revenue. Blood and egg samples were collected at three Maine Atlantic salmon farms from female broodstock at the time of spawning over a 2-year period. Correlative factors for reduced embryo survival were investigated by measuring egg and maternal plasma concentrations of 17β-estradiol (E2), 11-ketotestosterone (11-KT), testosterone and calcium, as well as maternal hepatic ethoxyresorufin-O-deethylase (EROD) activity and fork length. Significant positive correlations were found between maternal plasma concentrations of E2 and 11-KT and embryo survival. Interestingly, there was no correlation with egg concentrations of sex steroids and embryo survival, suggesting that embryo mortality does not likely rest with the maternal deposition of sex steroids into the egg, but with another hormone regulated process related to egg assembly, ovulation or post-ovulatory ageing.

Endocrine changes during the previtellogenic stage of the great sturgeon, Huso huso (Linnaeus, 1758)

The study aimed to investigate changes in serum concentrations of sex steroids, thyroid hormones, stress indices, cholesterol, triacylglycerol, calcium and phosphorus, as well as the growth in the 3-year old previtellogenic stage of great sturgeon, Huso huso over a 6-month period. Forty individually marked fish (mean weight 6913 g) were divided among three circular tanks under a natural temperature and photoperiod. Every 1.5 months fish were weighed and blood samples taken for serum analysis. Fish showed significant changes in 17β estradiol, testosterone, triiodothyronine (T3), thyroxine (T4), adrenocorticotropic hormone, cortisol, cholesterol, and phosphorus, but not in triacylglycerol and calcium concentrations. From the January onset of the experiment to the end of the trial in July, there was a decrease in sex steroids and cortisol concentrations as well as a decline in T3 concentrations from March and in T4 from February to July. The mean weight of fish increased significantly from the beginning to the end of the experiment. Although the oocyte diameter increased from 197 to 202 μm, the difference was not significant. The histological data on oocytes suggest that the great sturgeon, like the other sturgeons, has a heterogeneous asynchronous ovarian development in the early stage of reproduction. This data might be useful to the further understanding of the physiology of Huso huso and/or to improve its culture. Moreover, it leads to a general increase in the understanding of the basic reproductive biology of this valuable chondrostean species.

Unexplained postmenopausal uterine bleeding from atrophic endometrium: Histopathological and hormonal studies

Abstract Objective: To study the histopathology of endometrium and the serum concentration of sex steroid hormones in different types of atrophic endometrium associated with postmenopausal uterine bleeding (PMB). Design: Prospective observational study. Main outcome measures: Types of atrophic endometrium with PMB and serum concentration of sex steroid hormones in each type during and between episodes of bleeding. Materials and methods: One hundred and nine patients with PMB were investigated. Transvaginal ultrasonography was performed for all the cases. The endometrium was considered atrophic if its thickness was 1 ) and estradiol (E 2 ) and sex-hormone binding globulin were estimated for patients with atrophic endometrium during episodes of bleeding and in 47 cases were estimated also between episodes of bleeding. Results: Organic lesions were detected in 12 cases (11.0%) and atrophic endometrium was discovered in 97 cases (88.99%). The types of atrophic endometrium were as follow: atrophic inactive 46 cases (47.42%), atrophic/weakly proliferative 38 cases (39.19%), mixed with atrophic inactive and non-inactive 7 cases (7.21%) and cystic atrophic 6 cases (6.18%). Serum levels of all sex steroid hormones TT, A, E 1 , and E 2 were significantly higher in atrophic/weakly proliferative than atrophic inactive endometria. Serum concentration of these sex steroid hormones was significantly lower during episodes of bleeding than between these episodes. Conclusions: There are 4 histological types of atrophic endometrium, atrophic inactive, atrophic/weakly proliferative (non-inactive), mixed (inactive and non-inactive) and cystic atrophic. Serum concentration of sex steroid hormones T, A, E 1 , and E 2 was significantly higher and SHBG was significantly lower in cases of atrophic/weakly proliferative and mixed endometria than cases of atrophic inactive and cystic atrophic endometria. This may explain the development of endometrial adendocarcinoma on the top of atrophic endometrium. Concentration of these hormones was significantly higher between episodes of bleeding than during episodes of bleeding. This fluctuation may explain PMB from atrophic endometrium.

Novel use of the ovarian follicular pool to postpone menopause and delay osteoporosis

Life expectancy has increased by more than 30 years during the last century and continues to increase. Many women already live decades in menopause deprived of naturally produced oestradiol and progesterone, leading to an increasing incidence of menopause-related disorders such as osteoporosis, cardiovascular diseases and lack of general well-being. Exogenous oestradiol has traditionally been used to alleviate menopause-related effects.This commentary discusses a radical new method to postpone menopause. Part of the enormous surplus of ovarian follicles can now be cryostored in youth for use after menopause. Excision of ovarian tissue will advance menopause marginally and will not reduce natural fertility. Grafted tissue restores ovarian function with circulating concentrations of sex steroids for years in post-menopausal cancer survivors. Future developments may further utilize the enormous store of ovarian follicles.Currently, the main goal of ovarian cryopreservation is fertility preservation, but grafting of ovarian tissue may also serve endocrine functions as a physiological solution to prevent the massive medical legacy of osteoporosis and menopause-related conditions in the ageing population. This intriguing solution is now technically available; the question is whether this method qualifies for postponing menopause, perhaps initially for those patients who already have cryostored tissue?

Testosterone application decreases the capacity for ACTH and corticosterone secretion in a rat model of the andropause

The culminating phase of ageing in males–andropause is characterized by enhanced activity of the hypothalamic–pituitary–adrenal axis and frequent glucocorticoid excess. In parallel, free testosterone deficiency provides the baseline hormonal milieu for the ageing male. The aim of this study was to illustrate (using diverse microscopic and biochemical methodologies) the effects of testosterone application on the capacity for adrenocorticotropic hormone (ACTH) and corticosterone secretion in a rat model of the andropause. Middle-aged Wistar rats were divided into sham-operated (SO; n=8), orchidectomized (Orx; n=8) and testosterone treated orchidectomized (Orx+T; n=8) groups. Testosterone propionate (5mg/kg b.w./day) was administered for three weeks, while SO and Orx groups received the vehicle alone. ACTH cells and the adrenal cortex were stained using immuno-histochemical, immuno-fluorescent and histochemical procedures. Circulating concentrations of testosterone, estradiol, ACTH and corticosterone, as well as the adrenal tissue corticosterone levels were measured by immunoassays. Testosterone application led to increased (p<0.05) serum concentrations of sex steroids. Consequently, in Orx+T rats the ACTH cell nuclei volume increased (p<0.05) by 34%, while the volume density of ACTH cells and their relative intensity of fluorescence decreased (p<0.05) by 46% and 21%, respectively, in comparison with the corresponding parameters in the Orx group. Testosterone also induced vasodilatation in the adrenocortical zona fasciculata, and decreased (p<0.05) the ACTH concentrations and adrenal tissue corticosterone levels by 38% and 31%, respectively, compared to the Orx group. In conclusion, testosterone administration caused a decrease in the capacity for ACTH and corticosterone secretion in a rat model of the andropause.

Ejaculate parameters in patients with abdominal obesity

Objective: the definition of association of levels of sex steroid hormones and ejaculate parameters with different types of fat distribution in infertile men with overweight and obesity. Materials and methods. A total of 119 somatically healthy Russian men who contacted Novosibirsk Center of Reproductive Medicine in 2012–2014 with the problem of infertility have been examined. Based on the results of anthropometric surveys all the men were divided into 3 groups. The 1 st group included men with overweight, obesity, and upper type of fat distribution (the ratio of waist circumference (WC) to the hip circumference (HC) ≥ 0.95); the 2 nd group – men with overweight, obesity and lower type of fat distribution (WC/HC < 0.95); the 3 rd group – men with normal body weight. Questionnaires have been completed; determination in serum of concentrations of total testosterone, estradiol, sex hormones binding globulin (SHBG); free testosterone calculated. Special study of ejaculate included semen analysis, sperm morphology assessment by strict criteria of Kruger MAP test, NCA-test, analysis of DNA fragmentation of sperm. Results. In all 3 groups frequency of medical and social risk factors occurrence for infertility were analyzed: sexually transmitted infections, 88 chronic prostatitis, the systematic consumption of alcohol and smoking. It was revealed that these factors occurred with a high, but not significantly different frequency in men of 3 groups: the frequency of sexually transmitted infections in the 1 st , 2 nd and 3 rd groups was 65.8; 61.0 and 63.2 %; systematic consumption of alcohol – 85.4; 78.1 and 63.2 %; systematic smoking – 36.6; 53.7 and 34.21 %; chronic prostatitis – 68.3; 56.1 and 50.0 % respectively. The average concentrations of sex steroid hormones and SHBG in the serum of men of all groups did not go beyond the reference range. Patients of the 1 st and 2 nd groups had significantly lower concentration of total testosterone in serum compared with the third group, moreover the indicated decline was more pronounced in men of the 1 st group. The content of SHBG in serum was also significantly lower in the 1st and 2 nd groups in relation to the 3 rd group. Comparison of ejaculate indicators revealed significant differences in the 1 st and 2 nd groups of men, differing in the type of fat distribution, in terms of volume of ejaculate, share of progressively motile sperm and DNA fragmentation level. Differences are identified for some indicators of ejaculate between the 1 st and 3 rd groups, but the differences between the 2 nd and 3 rd groups on any indicator are not detected. Conclusion. The revealed differences indicate a negative effect on the ejaculate indicators, particularly of upper type of fat distribution, peculiar to the men of the 1 st group. The obtained results justify the assumption that abdominal obesity with upper type fat distribution is an independent risk factor of male fertility reduction.

The effects of salinity on reproductive performance and plasma levels of sex steroids in Caspian kutumRutilus frisii kutum

Sexually mature kutum, Rutilus frisii kutum, captured from its natural habits, the Caspian Sea and the Khoushkrood River, reared at 0.5 g L−1 and 8–13 g L−1 for approximately 1 year in experimental condition, for assessing the effect of salinity on reproduction. Plasma concentrations of sex steroid hormones (17β-estradiol, testosterone and 17α-hydroxyprogestrone) were measured in the three stages of gametogenesis. Female kutum held at <0.5 g L−1 or 8–13 g L−1 had no ovulated oocytes in their ovaries. In contrast, males held in captivity were spermiated, similar to their wild counterparts. The average sperm volume of males held at <0.5 g L−1 (2.36 ± 0.46 mL) was lower than males held at 8–13 g L−1 (3.65 ± 0.73 mL) at the end of the experimental period. The highest concentration of testosterone was observed in mid-gametogenesis in wild fish that was significantly higher than the concentration seen in fish held in either <0.5 g L−1 or 8–13 g L−1. Female kutum showed suppressed steroid hormones in captivity, resulting in failure in the gonad development. However, male kutum adapt well to captivity and showed synchrony in steroid hormone variations with the wild fish, resulting in the testicular development. Results of this study also indicate that salinity plays a minor, but vital, role in reproduction of kutum, a factor that needs to be considered for keeping broodstock of brackish water fish species like kutum.

Measurement of a Comprehensive Sex Steroid Profile in Rodent Serum by High-Sensitive Gas Chromatography-Tandem Mass Spectrometry.

Accurate measurement of sex steroid concentrations in rodent serum is essential to evaluate mouse and rat models for sex steroid-related disorders. The aim of the present study was to develop a sensitive and specific gas chromatography-tandem mass spectrometry (GC-MS/MS) method to assess a comprehensive sex steroid profile in rodent serum. A major effort was invested in reaching an exceptionally high sensitivity for measuring serum estradiol concentrations. We established a GC-MS/MS assay with a lower limit of detection for estradiol, estrone, T, DHT, progesterone, androstenedione, and dehydroepiandrosterone of 0.3, 0.5, 4.0, 1.6, 8, 4.0, and 50 pg/mL, respectively, whereas the corresponding values for the lower limit of quantification were 0.5, 0.5, 8, 2.5, 74, 12, and 400 pg/mL, respectively. Calibration curves were linear, intra- and interassay coefficients of variation were low, and accuracy was excellent for all analytes. The established assay was used to accurately measure a comprehensive sex steroid profile in female rats and mice according to estrous cycle phase. In addition, we characterized the impact of age, sex, gonadectomy, and estradiol treatment on serum concentrations of these sex hormones in mice. In conclusion, we have established a highly sensitive and specific GC-MS/MS method to assess a comprehensive sex steroid profile in rodent serum in a single run. This GC-MS/MS assay has, to the best of our knowledge, the best detectability reported for estradiol. Our method therefore represents an ideal tool to characterize sex steroid metabolism in a variety of sex steroid-related rodent models and in human samples with low estradiol levels.

Co-treatment with the non-steroidal anti-androgen drug, flutamide and the natural estrogen, 17β-estradiol does not lead to additive reproductive impairment in juvenile Murray rainbowfish (Melanotaenia fluviatilis).

The aim of this study was to investigate if the anti-androgen, flutamide, and the estrogen, 17β-estradiol work together to feminize juvenile Murray rainbowfish (Melanotaenia fluviatilis). Fish (60 days post-hatch) were exposed to 25 ng/L 17β-estradiol (E2), 25 µg/L flutamide (Flu low), 250 µg/L flutamide (Flu high), E2 + Flu low and E2 + Flu high. After 35 days of exposure, concentrations of sex steroid hormones, 17β-estradiol and 11-keto testosterone (11-KT), were determined in the head; and vitellogenin (VTG) concentration was measured in the tail. The abdomens were used for histological investigation of the gonads. Treatment with E2 + Flu high resulted in reduction in body weights and lengths in males and condition factor in females. Intersex was noted in Flu high and E2 + Flu high treatments. Exposures to E2 and/or Flu (low and high) resulted in precocious oocyte development but inhibited sperm development. The 17β-estradiol levels decreased significantly in the heads of both sexes after exposures to E2 and/or Flu (high and low). Flu high and E2 alone increased the 11-KT levels in both sexes. However, E2 + Flu low decreased 11-KT levels in males and increased them in females. Flutamide (low and high) induced VTG protein in the tails of both sexes. In males, VTG was not induced in the tail after exposure to E2. No significant effect of flutamide on E2-induced VTG concentration was noted. We conclude that co-treatment with flutamide and 17β-estradiol does not lead to additive reproductive impairment in juvenile Murray rainbowfish.

Non-invasive endocrine monitoring of ovarian and adrenal activity in chinchilla (Chinchilla lanigera) females during pregnancy, parturition and early post-partum period

The chinchilla is a rodent that bears one of the finest and most valuable pelts in the world. The wild counterpart is, however, almost extinct because of a drastic past and ongoing population decline. The present work was developed to increase our knowledge of the reproductive physiology of pregnancy and post-partum estrus in the chinchilla, characterizing the endocrine patterns of urinary progesterone, estradiol, LH and cortisol metabolites throughout gestation and post-partum estrus and estimating the ovulation timing at post-partum estrus.Longitudinal urine samples were collected once per week throughout pregnancy and analyzed for creatinine, cortisol, LH, estrogen and progesterone metabolite concentrations. To indirectly determine the ovulation timing at post-partum estrus, a second experiment was performed using pregnant females subjected to a post-partum in vivo fertilization scheme. Urinary progestagen metabolites increased above baseline levels in early pregnancy between weeks-8 and -11 respectively to parturition, and slightly declined at parturition time. Urinary estrogens showed rising levels throughout mid- and late pregnancy (weeks-9 to -6 and a further increase at week-5 to parturition) and decreased in a stepwise manner after parturition, returning to baseline levels two weeks thereafter. Cortisol metabolite levels were relatively constant throughout pregnancy with a tendency for higher levels in the last third of gestation and after the pups’ birth. Parturition was associated with dramatic reductions in urinary concentrations of sex steroids (especially progestagens). Observations in breeding farms indicated that the females that resulted in a second pregnancy after mating, did so on the second day after parturition. These data were in agreement with an LH peak detected 24h after parturition. Urinary steroid hormone patterns of estrogen and progestagen metabolites provided valuable information on endocrine events during pregnancy and after parturition in the chinchilla. Results presented in this study enhance our understanding of natural reproductive dynamics in the chinchilla and support empirical observations of breeders that post-partum ovulation occurs ∼48h after parturition.

Evidence that progestins play an important role in spermiation and pheromone production in male sea lamprey (Petromyzon marinus)

Progestins (progestogens, C21 steroids) have been shown to regulate key physiological activities for reproduction in both sexes in all classes of vertebrates except for Agnathans. Progesterone (P) and 15α-hydroxyprogesterone (15α-P) have been detected in sea lamprey (Petromyzon marinus) plasma, but the expression patterns and functions of putative progestin receptor genes have not yet been investigated. The first objective of this study was to determine the differences in mRNA expression levels of nuclear progestin receptor (nPR) and the membrane receptor adaptor protein ‘progesterone receptor membrane component 1’ (pgrmc1) in putative target tissues in males at different life stages, with and without lamprey GnRH-I and -III treatment. The second objective was to demonstrate the function of progestins by implanting prespermiating males (PSM) with time-release pellets of P and measuring the latency to the onset of spermiation and plasma concentrations of sex pheromones and steroids. The third objective was to measure the binding affinity of P in the nuclear and membrane fractions of the target tissues. Expression levels of nPR and pgrmc1 differed between life stages and tissues, and in some cases were differentially responsive to lamprey GnRH-I and -III. Increases in nPR and pgrmc1 gene expressions were correlated to the late stages of sexual maturation in males. The highest expression levels of these genes were found in the liver and gill of spermiating males. These organs are, respectively, the site of production and release of the sex pheromone 3 keto-petromyzonol sulfate (3kPZS). The hypothesis that pheromone production may be under hormonal control was tested in vivo by implanting PSM with time-release pellets of P. Concentrations of 3kPZS in plasma after 1week were 50-fold higher than in controls or in males that had been implanted with androstenedione, supporting the hypothesis that P is responsible for regulating the production of the sex pheromone. P treatment also accelerated the onset of spermiation. Saturation and Scatchard analyses of the target tissues showed that both nuclear and membrane fractions bound P with high affinity and low capacity (KD 0.53pmol/g testis and 0.22pmol/g testis, and Bmax 1.8 and 5.7nM, respectively), similar to the characteristics of nPR and mPR in other fish. The fact that a high proportion of P was also converted in vivo to 15α-P means that it is not yet possible to determine which of these two steroids is the natural ligand in the sea lamprey.