Concentrations Of Sexual Steroids Research Articles

Cortisol, DHEA, and Sexual Steroid Concentrations in Fattening Pigs' Hair.

Simple SummaryThe rearing of heavy pigs in Italy is an important part of the production of Protected Designation of Origin (PDO) hams. Along with the standard quality characteristics, the quality of products with animal origin is also assessed by the level of animal welfare. Evaluation of hair steroid concentrations has been considered an effective approach to assess stress in mammals. The advantage of using hair for this process is that it provides an integrated measure of hormone concentrations over medium- and long-term periods, it can be simply and non-invasively collected, and it does not require any special expedient for storage. The aim of this study was to evaluate the hair cortisol, dehydroepiandrosterone (DHEA), and sexual steroid concentrations in fattening pigs at 36 weeks of age before slaughtering through a non-invasive approach. Females had significantly higher cortisol levels, significantly lower concentrations of DHEA, and significantly higher cortisol/DHEA ratios than barrows. Progesterone was significantly higher in gilts than in barrows. Testosterone and 17β-estradiol were significantly higher in barrows than in gilts. These results will allow us to plan future research with the aim of identifying threshold values in order to set up strategies to control the allostatic load and to increase the resilience of fattening pigs.The aim of this study was to analyze the feasibility and reliability of using hair as a matrix to determine the dehydroepiandrosterone (DHEA) and sexual steroid concentrations and the cortisol/DHEA ratio in fattening pigs. The results could be also used to plan future research to identify threshold values in order to set up strategies to control the allostatic load and increase the resilience of fattening pigs before slaughter. The study was conducted on 107 commercial crossbred rearing pigs. The hair samples were taken by shaving at the age of 36 weeks, and concentrations of the hormones were measured using a solid-phase microtiter radioimmunoassay. Females had significantly higher cortisol levels (p < 0.01), significantly lower DHEA concentrations (p < 0.05) and significantly higher cortisol/DHEA ratios (p < 0.01) than barrows. Progesterone was significantly higher in gilts than in barrows (p < 0.01). Testosterone and 17β-estradiol were significantly higher in barrows than in gilts (p < 0.05). If future research can produce threshold values for the different markers examined, the evaluation of animals under subclinical stress conditions will be possible.

Reproductive cycle of leopard grouper Mycteroperca rosacea (Streets, 1877) held in captivity: relation ship between gonad development and sex steroid concentration

In this study, sex steroids (E2, T, and 11-KT) concentrations in blood of captive leopard grouper ( Mycteroperca rosacea ) and their relation togonad development were determined during a reproductive cycle. Each month, gonad samples from 24 fish were obtained to analyze gonadal maturation and blood was extracted to determine steroid levels. Throughout the year, ovaries showed a higher percentageof primary oocytes. In January, oocytes at early and late vitellogenesis stages increased progressively; from March to June, ovulation rates were high. In females, estradiol levels increased from March and decreased after the spawning season. Lower levels of testosterone were found during the spawning season and 11-KT remained without significant changes throughout the year. Males exhibit a significant increase in E2 from March until July; testosterone remained without significant variation throughout theyear, and 11-KT plasma levels increased from March until July and decreased after the spawning season. In this study, we verified the sex change of an organism and the concentrations of sexual steroids were determined and discussed.

One year daily changes in fecal sexual steroids of two captive female cheetahs (Acinonyx jubatus) in Italy

The present study evaluated changes of fecal sexual steroids in two female cheetahs (Geijsha and Duchessa) in Northern Italy throughout one year. Wet feces were collected daily from two sibling animals of the same age, housed with conspecific males and managed in the same conditions, and estrogens and progestogens concentrations were analyzed by radioimmunoassay (RIA).Evidence of ovarian activity based on regular fluctuation in estrogen excretion was demonstrated in both females. None of the animals was continuously cycling, as follicular activity was interrupted by anestrous periods, during the spring and early winter. No significant increases of progestogens were recorded after the estrogen peaks, indicating that induced or spontaneous ovulations did not occur during the observation period. The wavelet decomposition evidenced the temporal pattern of ovarian activity in the two females, underlying throughout the year a more pronounced rhythmical ovarian estrogenic activity in Geijsha than in Duchessa. However, this statistical approach had a smoothing effect in depicting the hormonal patterns and the number of follicular phases might be lower than that revealed by the iterative method.In this study, RIA on wet feces performed very well to determine sexual steroid concentrations, and an ovarian activity interrupted by anestrous periods along the year in captive cheetahs co-housed in a small group was demonstrated.More information on estrous behavior of captive cheetahs were obtained in this study, but the effects of husbandry and management conditions on natural reproductive physiology of this species remain to elucidate.

Effects of extending the length of pro-oestrus in an oestradiol- and progesterone-based oestrus synchronisation program on ovarian function, uterine environment and pregnancy establishment in beef heifers.

The aim of the present study was to investigate the effects of a strategy for extending pro-oestrus (the interval between luteolysis and ovulation) in an oestrus synchronisation protocol (named J-Synch) in beef heifers on follicular growth, sexual steroid concentrations, the oestrogen receptor ERα and progesterone receptors (PR) in the uterus, insulin-like growth factor (IGF) 1 and pregnancy rates. In Experiment 1, heifers treated with the new J-Synch protocol had a longer pro-oestrus period than those treated with the conventional protocol (mean (±s.e.m.) 93.7±12.9 vs 65.0±13.7h respectively; P<0.05). The rate of dominant follicle growth from the time of progesterone device removal to ovulation was greater in heifers in the J-Synch than conventional group (P<0.05). Luteal area and serum progesterone concentrations were greater in the J-Synch Group (P<0.05) for the 12 days after ovulation. Progesterone receptor (PGR) staining on Day 6 after ovulation in the uterine stroma was lower in the J-Synch than conventional group (P<0.05), and the expression of PR gene (PGR) and IGF1 gene tended to be lower in J-Synch-treated heifers (P<0.1). In Experiment 2 (n=2349), the pregnancy rate 30-35 days after fixed-time AI (FTAI) was greater for heifers in the J-Synch than conventional group (56.1% vs 50.7% respectively). In conclusion, our strategy for extending pro-oestrus (i.e. the J-Synch protocol) significantly improves pregnancy establishment in beef heifers. This improvement was related to an increased rate of growth of the dominant ovulatory follicle, greater progesterone concentrations during the ensuing luteal phase and different uterine patterns of PGR and IGF1, which may have favoured embryo development and pregnancy establishment.

Histologic effect of a postnatal slow-release GnRH agonist on feline gonads

In postnatal domestic cats, GnRH agonists suppressed fecal concentrations of sexual steroids and delayed puberty. The aim of this study was to describe the gross and microscopic morphometric effects of a single administration of the GnRH agonist, deslorelin acetate, on the gonads of postnatally treated cats. Twenty-seven postnatal male (n = 14) and female (n = 13) kittens were randomly assigned to one of the following treatment groups within the first 24 hours of birth: deslorelin acetate (1.6 mg, subcutaneous; DA, n = 16) or control that remained untreated (CO, n = 11) and spayed or castrated immediately after the onset of puberty. After surgical removal, the gonads were gross and histologically assessed. Sertoli cells also were examined immunohistochemically. Comparisons between the treatments were carried out by the Student t test. Gross gonadal wet weight and volume as well as gonadosomatic index were significantly lower in the DA than those in the CO males; these same parameters were not different in females. Primordial (461.4 + 3.0 vs. 1074.3 + 117.5; P < 0.01), primary (59.1 + 13.5 vs. 165.4 + 24.6; P < 0.01), and secondary (17.5 + 2.6 vs. 31.17 + 8.1; P < 0.05) follicles per mm2 were decreased in DA than in CO gonads. Epididymal sperm motility and morphology were normal in all but two DA cats that had too few sperm to be evaluated. Germinal epithelial height (μm; 39.68 + 0.92 vs. 72.7 + 1.2; P < 0.01) and most of their cellular components as well as the Sertoli (cm3; 0.1 + 0.02 vs. 0.24 + 0.05; P < 0.01) cells were diminished in the DA cats. Gonadotropin-releasing hormone agonist endocrine disruption during the neonatal critical reproductive time window may have a potential as a contraceptive agent in domestic felids.

Treatment of GnRHa-implanted Senegalese sole (Solea senegalensis) with 11-ketoandrostenedione stimulates spermatogenesis and increases sperm motility

The effect of 11-ketoandrostenedione (OA) on plasma concentrations of sexual steroids and spermatogenesis of Senegalese sole (Solea senegalensis) implanted with gonadotropin-releasing hormone agonist (GnRHa) was investigated. Males were treated with saline (control) or with GnRHa implants (50 mug kg(-1)) in the presence or absence of OA (2 or 7 mg kg(-1)) during twenty eight days. Treatment with GnRHa alone slightly stimulated spermatogenesis and milt production with respect to controls, and this was associated with a transient elevation of plasma 11-ketotestosterone (11-KT) at day seven and an increase of 5beta-reduced metabolite(s) of 17,20beta-dihydroxy-pregn-4-en-3-one (17,20betaP) at day twenty eight. However, treatment with GnRHa+OA increased plasma concentrations of 11-KT and free+sulphated 5beta-reduced metabolites of 17,20betaP at days seven, fourteen and twenty one. After twenty eight days, the testis of GnRHa+OA-treated fish showed a lower number of spermatogonia B and spermatocytes I, and a higher number of spermatids, than fish treated with GnRHa alone. In addition, the motility of spermatozoa produced by GnRHa+OA males was enhanced by 2-fold with respect to controls or GnRHa males. These results suggest that treatment of Senegalese sole with GnRHa+OA stimulates spermatogenesis resulting in more motile sperm. Such effects could be mediated by an increased synthesis of 11-KT and/or 17,20betaP in the testis but further studies will be required to elucidate the specific mechanism involved.

Endocrine Disruption and Flame-Retardant Chemicals: PBDE-99 Effects on Rat Sexual Development

Chemical flame retardants containing polybrominated diphenyl ethers (PBDEs) have attracted growing attention in recent years from toxicologists. Unlike their chemical cousins, dioxins and polychlorinated biphenyls (PCBs), environmental levels of PBDE compounds are increasing, as are concentrations found in human breast milk. This is of concern because of the potential that PBDEs may cause developmental toxicity due to endocrine-modulating effects, as has previously been documented with dioxins and PCBs. Results of a new German study examining developmental exposure in rats to a commonly used and environmentally abundant PBDE compound, PBDE-99, lend support to suspicions that PBDEs can have detrimental effects on sexual development in the offspring of exposed mothers [EHP 114:194–201]. The researchers examined sexual development end points—circulating sexual steroid concentrations, reproductive organ development, and sexually dimorphic behavior—that have been shown in similar rodent experiments to change following exposure to a mixture of PCBs reconstituted according to the congener pattern found in human breast milk. In the current study, weight-matched groups of dams received daily subcutaneous injections of PBDE-99 from gestational days 10 through 18 at doses of 1 or 10 milligrams per kilogram body weight (mg/kg). For comparison, another group was dosed with 30 mg/kg of the PCB mixture Aroclor 1254 (A1254). In PBDE-exposed male offspring, pronounced decreases in circulating sex steroids (estradiol, testosterone) were seen both at weaning and in adulthood. Anogenital distance, an androgen-dependent marker of sexual development, was also reduced in the male offspring. The males further displayed a dose-dependent increased preference for sweets, which is a sexually dimorphic behavior in rodents—this finding indicates feminization in the males. A slight acceleration in onset of puberty was noted in the low-dose group. The PBDE-exposed females had less severe effects. Onset of puberty was mildly delayed in the high-dose group. Also, the number of primordial/primary (rudimentary) ovarian follicles was reduced in the low-dose group, with a more pronounced decline in secondary (more developed) follicles within the high-dose group. These results could indicate an impaired reproductive life span, in that ovarian follicles are a key indicator of ovarian health. The females also had an insignificant increase in sweet preference. The researchers found no effect on sweet preference in male or female offspring exposed to the PCB mixture, but in the females they did see a significant increase in the number of tertiary (still larger, more developed) follicles. The exposure also adversely affected steroid concentrations in males and sexual development in both sexes. Thus, it appears that the pattern of endocrine-disruptive effects differs for PBDE-99 and A1254, which may be due to the higher content of dioxin-like compounds in the PCB mixture. The scientists also examined organ weights as an indicator of overall development in the rodents. They found that pituitary gland weights were slightly decreased in males in the PBDE-99 high-dose group at weaning, while they were increased in females in the low-dose group. The authors speculate that these effects may indicate a biphasic response to PBDE-99, and suggest that the phenomenon should be studied further in future research. Results also included a marked dose-dependent decrease in thyroid gland weight in adult rats of both sexes exposed to either PBDE-99 or A1254. This study adds to a growing body of literature indicating that chemical flame retardants are endocrine-disrupting compounds with the potential to profoundly affect sexual development and sexually dimorphic behaviors. The fact that several effects were seen in adulthood, long after termination of the exposure, indicates that the rats’ gestational exposure caused permanent physiologic damage. With increases in human body burden and environmental levels, and with the compounds’ apparent persistence in both venues, it is safe to assume that PBDEs will be the focus of more urgent research activity.

Female-specific aspects in the pharmacotherapy of chronic cardiovascular diseases

Differences in pharmacokinetics, pharmacodynamics, and physiology contribute to the phenomenon that women and men frequently respond differently to cardiovascular drugs. Hormonal influences, in addition, can play an important role: for example, the menstrual cycle, menopause, and pregnancy--as a result of fluctuations in concentrations of sexual steroids, and of changes in total body water--can be associated with gender-specific differences in the plasma levels of cardiovascular drugs. Clinical relevance accordingly results, especially for substances with a narrow therapeutic margin. This review treats the most important pharmacodynamic gender-relevant differences in this context, and surveys available evidence on the benefits of therapy of chronic cardiovascular diseases in women. On the whole, the study situation for women is appreciably less favourable than for men: owing to the fact that women are under-represented in most studies, and that few gender-specific analyses have been conducted.

Influence of ovariectomy on metabolic and endocrine parameters during sexual development in the female pig.

During pubertal maturation, the increase in blood concentrations of sexual steroids is associated with a spurt in plasma IGF-I in primates, rats and cattle. However, data on the influence of sex steroids on plasma IGF-I during this physiological period are contradictory. Therefore, the present experiment was undertaken to understand better the relationships between pubertal development, energy metabolic regulation and the IGF-I/IGFBP system in crossbred gilts (Large White x Landrace). Circulating concentrations of hormones and metabolites were examined in ovariectomized (n = 6) and sham-operated females (n = 9) during sexual development. Surgery and first blood samplings were performed at 70 days of age. Growth curves were similar in ovariectomized and entire females. First oestrus and ovulation occurred between 178 and 209 days in entire gilts. From 84 days of age, plasma FSH concentration was lower in sham-operated than in ovariectomized gilts (P < 0.01) showing the negative feedback exerted by ovarian secretions on the gonadotrophin axis in entire gilts. Preprandial concentration of plasma glucose was not influenced by age whereas plasma free fatty acids decreased with age (P < 0.01). Concentrations of both metabolites were similar in ovariectomized and entire gilts. Plasma IGF-I and 43-39 kDa IGFBP levels increased whereas plasma 34 kDa IGFBP decreased with age (P < 0.01) and none of the levels differed between ovariectomized and entire gilts (P > 0.1). This experiment shows that gonadal steroids are not involved or play only a minor role in the control of IGF-I and IGFBP plasma levels during pubertal development in the female pig.

C.E.B.A.S.-AQUARACK: Second generation hardware and latest scientific results

A second version of the C.E.B.A.S.-AQUARACK laboratory prototype was developed which includes a new water recycling system and a “Botanical Component” with higher water plants for nitrate elimination. It was a modified by a compact commercial filter system which involves a semi-biological coarse filter, a bacteria filter, gas and heat exchangers and a UV sterilization device. A highly sophisticated process control system offers all possiblities to implement robotics and telescience. With the installation of the Botanical component into the system the first step of the realisation of the conception of a “Closed Equilibrated Biological Aquatic System” is performed. In the scientific frame program the reproductive biology of the main experimental animal, Xiphophorus helleri, plays an important role. After the establishment of a morphological reference system of the stages of sexual maturity in both sexes this is correlated with relevant physiological data as concentrations of sexual steroids in gonadal tissue and plasma. On the brain-pituitary level the ontogeny of the gonadotropin releasing hormone (GnRH) and the gonadotropin (GtH) systems were investigated by immunohistochemistry. Surprisingly gonadotropin was not only localized in the pituitary gland but also in brain neurons and fibers which undergo a distinct ontogenetic development and a maior part of which are in close structural relation to the GnRH system. A special chapter pays attention to the role of the C.E.B.A.S.-system in C.E.L.S.S. research.

Endocrine regulation of the endometrium throughout the menstrual cycle (author's transl)

Estradiol, estrone, and progesterone levels in serum and tissue were determined radioimmunologically from 160 endometrium and serum samples taken at various phases of the menstrual cycle in female patients who had undergone either curettage or hysterectomy for medical reasons. In addition, the cytoplasmatic estradiol and progesterone receptor concentrations and the (17beta-HSD) 17-beta-hydroxysteroid dehydrogenase activities in the endometrium were measured. In 132 cases, it was possible to correlate the endometrial histological findings and serum hormone levels with a particular phase of the cycle. The serum concentrations of sexual steroids displayed the usual biphasal pattern for estradiol and estrone with the postovulatory increase in progesterone. The tissue levels of these hormones followed a course partly paralled to and partly opposed to the serum levels. The progesterone profile in tissues essentially matches that in the serum except that the endometrium concentrations showed a marked prevulatory increase, with no appreciable postovulatory rise. The midcycle estradiol peak was also observed in the endometrium. After ovulation, the estradiol concentration in the tissue declined significantly. The changes in estrone levels in the secretory endometrium were at variance with those in the serum, increasing sharply after ovulation. The cytoplasmic estradiol receptor concentration exhibited a maximum in the middle of the proliferative phase and declined steadily over the rest of the cycle. The number of progesterone-binding receptors is only enhanced at midcycle. The concentration changes in the progesterone receptors could be clearly correlated with the estradiol peak in serum and tissue at midcycle. A 10-fold increase in 17beta-HSD activity is observed after ovulation, affecting changes in the tissue/serum estradiol and estrone ratios. The estradiol shifts ratio in favor of the serum during postovulatory phase, whereas the estrone ratio is displaced in favor of the tissue. A regulatory model for the endometrial cells during the menstrual cycle is suggested on the basis of the results obtained.