Plasma Estradiol Concentrations Research Articles

Ovarian surface epithelium receptors during pregnancy and estrus cycle of rats with emphasis on steroids and gonadotropin fluctuation

The present study is designed to demonstrate the ovarian surface epithelial cells’ (OSE) estrogen receptor α (ERα) and progesterone receptor (PR) during pregnancy and estrous cycle in rat. Moreover, determination of the levels of plasma progesterone, estradiol, FSH and LH was also made. The levels of plasma progesterone, estradiol, FSH and LH concentrations were determined on days 7 (n=5), 14 (n=5), and 21 (n=5) of pregnancy in three groups of rats and during the estrous cycle (n=5) using an ELISA kit. Immunohistochemical method for PR and ERα expressions was also made on the ovary. During pregnancy, FSH and LH remained low except at term when LH levels began to increase from 16ng/ml to 47ng/ml. Progesterone levels significantly exceeded estradiol values in all pregnant rats with a peak value of 202ng/ml on day 14. Elevated progesterone levels were associated negatively with LH and estradiol levels during pregnancy. The levels of estradiol surged significantly on day 21. Immunohistochemistry of the ovary showed low levels of OSE cells staining positive for ERα expression. ERα positive cells were absent on day 7 and 14 of pregnancy, only day 21 recorded a very low percentage of immunostaining (0.5%) within the nuclei of OSE cells. On the contrary, immunostaining of PR was not observed within the nuclei of OSE cells in all groups of study. In conclusion, these results may suggest that the progesterone effect during pregnancy seems to be overriding the positive effect of estrogens on OSE cells. High progesterone levels may have a direct negative effect on gonadotropin production and thereby it might inhibit events leading to both follicular development and OSE proliferation. Understanding the factors affecting OSE proliferation may help elucidating the mechanism(s) of assisted diseases such as ovarian cancer.

Comparison of the Vaginal environment of Macaca mulatta and Macaca nemestrina Throughout the Menstrual Cycle

Pigtail macaques, Macaca nemestrina (PT), are more susceptible to vaginal transmission of simian immunodeficiency virus (SIV) and other sexually transmitted diseases (STD) than rhesus macaques (RM). However, comparative studies to explore the reasons for these differences are lacking. Here, we compared differences in hormone levels and vaginal mucosal anatomy and thickness of RM and PT through different stages of the menstrual cycle. Concentrations of plasma estradiol (E2) and progesterone (P4) were determined weekly, and vaginal biopsies examined at days 0 and 14 of the menstrual cycle. Consistent changes in vaginal epithelial thickness occurred at different stages of the menstrual cycle. In both species, the vaginal epithelium was significantly thicker in the follicular than in luteal phase. Keratinized epithelium was strikingly much more prominent in RM, especially during the luteal phase. Further, the vaginal epithelium was significantly thinner, and the P4:E2 ratio was higher in PT during luteal phase than RM. Striking anatomic differences in the vaginal epithelium between rhesus and pigtail macaques combined with differences in P4:E2 ratio support the hypothesis that thinning and less keratinization of the vaginal epithelium may be involved in the greater susceptibility of pigtail macaques to vaginal transmission of SIV or other STD.

Effects of erythropoietin on ischemia, follicular survival, and ovarian function in ovarian grafts

Ovarian tissue transplantation is performed to preserve fertility in patients undergoing chemotherapy and radiotherapy. However, ischemia/reperfusion (IR) injury and free radical production occurring during the revascularization of the transplanted tissue are the major limitations of this procedure. The aim of this study was to investigate the effect of erythropoietin (EPO) as an antioxidant on oxidative stress and ovary survival following transplantation. The Naval Medical Research Institute (NMRI) mice (4-5 weeks old) were divided into three groups (six mice per group): control; autograft+saline, and autograft+EPO (500 IU/kg i.p.). After 28 days, ovary compartments were estimated stereologically. DNA fragmentation and plasma malondialdehyde (MDA), progesterone, and estradiol (E2) concentrations were also evaluated. The results were analyzed using one-way ANOVA and Tukey's test, and the means were significantly different at P<0.05. The mean total volume of ovary, cortex, and medulla and the number of follicles increased significantly in the autograft+EPO group (P<0.01). Apoptosis rate in the autograft+EPO group was lower than that in the autograft+saline group. The concentration of MDA decreased significantly in the autografted EPO-treated group than in the autografted saline-treated group (P<0.01). The concentration of E2 increased significantly in the autograft+EPO group than in the autograft+saline group (P<0.01). EPO reduced IR injury, increasing follicle survival and function in grafted ovaries. Free Persian abstract A Persian (Farsi) translation of the abstract is freely available online at http://www.reproduction-online.org/content/147/5/733/suppl/DC1.

Biological responses of marine flatfish exposed to municipal wastewater effluent

There is increasing concern over the presence of pharmaceutical compounds, personal care products, and other chemicals collectively known as contaminants of emerging concern (CECs) in municipal effluents, yet knowledge of potential environmental impacts related to these compounds is still limited. The present study used laboratory exposures to examine estrogenic, androgenic, and thyroid-related endocrine responses in marine hornyhead turbot (Pleuronichthys verticalis) exposed to CECs from municipal effluents with 2 degrees of treatment. Fish were exposed for 14 d to environmentally realistic concentrations of effluent (0.5%) and to a higher concentration (5%) to investigate dose responses. Plasma concentrations of estradiol (E2), vitellogenin (VTG), 11-keto testosterone, and thyroxine were measured to assess endocrine responses. Contaminants of emerging concern were analyzed to characterize the effluents. Diverse types of effluent CECs were detected. Statistically significant responses were not observed in fish exposed to environmentally realistic concentrations of effluent. Elevated plasma E2 concentrations were observed in males exposed to ammonia concentrations similar to those found in effluents. However, exposure to ammonia did not induce VTG production in male fish. The results of the present study highlight the importance of conducting research with sentinel organisms in laboratory studies to understand the environmental significance of the presence of CECs in aquatic systems.

Importance of hormonal changes during the periparturition period in black Bengal goats

Background and Aim: The maintenance of pregnancy in livestock requires specific metabolic and functional changes between conception and the end of gestation, mediated through the interplay of hormones. The objectives of this study were to delineate the changes in plasma progesterone, estradiol, triiodothyronine (T 3 ), thyroxine (T 4 ), insulin, and cortisol concentrations during periparturient period in black Bengal goats and to elucidate the interrelationship between T 4 and cortisol in building up of the estradiol prior to parturition. Methods: The blood samples were collected on days −25, −20, −15, −10, and −5 with respect to the date of expected kidding, on the day of kidding (day 0) and also on days 5, 10, 15, 20, and 25 postpartum. Plasma was separated and stored at −20΀C until assay of hormones by radioimmunoassay. Results: Plasma progesterone concentration declined from day − 25 abruptly to the day of kidding and remained at basal level up to day 25 postpartum; whereas, plasma estradiol concentration declined abruptly from the day of kidding to a lower level than that of prepartum. Plasma insulin concentration declined ( P th postpartum. Plasma T 3 and T 4 concentrations decreased from day 25 prepartum to the day of kidding which increased by day 25 postpartum. Conclusion: Plasma estradiol was positively correlated with cortisol and T 4 indicating that changes in cortisol and T 4 levels contribute to increase in estradiol prior to delivery and therefore may directly influence the process of parturition.

75 DETECTION OF EMBRYONIC DEATH BY MONITORING OVARIAN STEROIDS BALANCE AND ULTRASONOGRAPHY IN JAPANESE BLACK CATTLE

In beef cattle, 20 to 44% embryonic loss occurs during the early stages of pregnancy (Humblot et al. 2001). However, the mechanism of early and late embryonic death is not clear. We investigated occurrence of embryonic death by monitoring ovarian hormones dynamics and checking for the presence of the conceptus after artificial insemination or embryo transfer in beef cattle. Twenty Japanese black females were inseminated (AI) and 12 females were transferred with 1 embryo (ET). Blood samples were collected on Days 21, 24, 28, 38, 48, 58, and 68 post-oestrus (oestrus = Day 0) and then stored at –30°C. Progesterone (P4) and oestradiol (E2) plasma concentrations were analysed using a chemiluminescent immunoassay. On each day of blood sampling, ovaries and presence of a conceptus in the uterus were monitored by ultrasonography. At Day 24 post-oestrus, the presence of the fetus was detected in 8 females (AI, n = 6; ET, n = 2), whereas only 3 females were confirmed to be pregnant at Day 28 and Day 38 post-oestrus. No embryo loss was seen at later stages of pregnancy (Days 48, 58, and 68 post-oestrus). At Day 21 post-oestrus, the conceptus could not be detected by ultrasonography but the E2/P4 ratio provided indication on the pregnancy status of the females that were classified as pregnant (n = 8) or not pregnant (n = 24) at day 24 post-oestrus (1.7 ± 2.2 versus 28.0 ± 34.2 respectively; mean ± s.d.). In the nonpregnant females compared with the pregnant ones at Day 24 post-oestrus, P4 declined below 1 ng mL–1 (0.6 ± 0.2 ng mL–1 v. 8.6 ± 3.9 ng mL–1), whereas E2 blood level remained stable (15.7 ± 21.9 v. 18.1 ± 1.1 pg mL–1). The decrease in P4 levels led to an increase in E2/P4 ratio (1.3 to 37.3 on Day 24). Our study suggests that a large proportion of embryo loss (75%) occurs before Day 24, whereas an additional 16% loss was seen between Day 24 and Day 28 post-oestrus. This embryo loss was shown to be associated with the altered balance of ovarian hormones.

Lactation is associated with increased plasma concentrations of oestradiol 17ß in early pregnant mares

Oestradiol 17b is the major biologically active oestrogen thought to be responsible for the behavioural and physical changes associated with sexual receptivity, ovulation, and preparation of the reproductive tract for insemination. In mares, plasma oestradiol 17b concentrations are typically low, around 10-20 pg/ml, and surprisingly exhibit only a relatively minor increase prior to ovulation...

78 THE PERIOVULATORY ENDOCRINE MILIEU AFFECTS THE OXIDATIVE STRESS CONTROL ON ENDOMETRIUM OF COWS

Acknowledging that the local oxidative profile (pro or antioxidant) may influence the control of very specific mechanisms such as intracellular signalling as well as the unspecific damage caused by oxidative stress, it is proposed that the balance between reducing and oxidative activities of the uterine environment (i.e. the REDOX profile) is regulated by exposure to ovarian steroids. The aim of this study was to verify the effect of the periovulatory endocrine milieu on concentrations of reactive oxygen species (ROS), activity of antioxidant enzymes, and lipid peroxidation profile on the endometrial tissue of cows in early diestrus. Eighty-three cyclic, nonlactating Nelore cows received an intravaginal progesterone (P4) device and an injection of oestradiol benzoate (E2) on Day –10. Animals were divided into 2 groups to receive sodium cloprostenol (PGF; large follicle group; LFG; N = 42) or not (small follicle group; SFG; N = 41) on Day –10. Progesterone devices were removed and prostaglandin F2α was injected between Day –2.5 and Day –1.75 in cows from LFG, and between Day –1.5 and Day –1.25 in cows from SFG. Ovulation was induced with GnRH on Day 0. Progesterone and oestradiol plasma concentrations were quantified. Animals were slaughtered on Day 7, when endometrial tissue was collected. A subgroup of ovulated cows (n = 9 per group) was selected to assess the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Furthermore, the content of reduced glutathione (GSH) and ROS by spectrofluorometry and lipid peroxidation by assessment of malondialdehyde concentrations were determined. Statistical comparisons between groups were performed by ANOVA (Statistica 4.5; StatSoft Inc., Tulsa, OK, USA). Maximum diameter of the preovulatory follicle (mean ± s.e.m.; 13.36 ± 0.29 v. 11.11 ± 0.33 mm, respectively; P &lt; 0.01), plasma concentrations of P4 on Day 7 (3.71 ± 0.25 v. 2.62 ± 0.26 ng mL–1; P &lt; 0.01) and E2 on Day 0 (2.94 ± 0.28 v. 1.27 ± 0.2 pg mL–1; P &lt; 0.01) were greater in LFG compared with SFG. The SFG showed lower enzymatic activity for CAT (0.79 ± 0.09 v. 0.5 ± 0.07 U mg–1 of protein; P &lt; 0.01) and GPx (2.43 ± 0.39 v. 2.0 ± 0.35 nmol of NADPH/min/mg of protein; P &lt; 0.05) than LFG. Additionally, lipid peroxidation was increased in SFG (177.68 ± 46.46 v. 255.71 ± 40.64 nmol of MDA/g of tissue; P &lt; 0.01), similarly to SOD activity (37.76 ± 3.95 v. 44.77 ± 7.66 IU; P &lt; 0.05). Concentrations of ROS and GSH were not different between groups. In conclusion, the periovulatory endocrine environment alters antioxidant mechanisms in the endometrium of cows in early diestrus. Specifically, it is proposed that the greater antioxidant activity observed on the LFG provided an environment that was less prone to lipid peroxidation than that from the SFG. The increase in SOD activity suggests a compensatory mechanism triggered by an environment potentially more oxidative observed on the SFG. The REDOX profile observed on the experimental groups may be associated with higher fertility observed in cows with higher E2 and P4 concentration during the proestrus and early diestrus, respectively. We acknowledge support from CNPq, FAPESP; Ourofino, CCPS-USP.

Biological Significance of Calbindin-D9k within Duodenal Epithelium

Calbindin-D9k (CaBP-9k) binds calcium with high affinity and regulates the distribution of free calcium in the cytoplasm. The expression of CaBP-9k is detected primarily in intestine that is vitamin D target tissue, and accumulates in the enterocytes of the duodenal villi. These enterocytes are the clearest example of vitamin D responsive cells, and the presence of CaBP-9k within them accentuates calcium absorption mediated by active transcellular calcium transport. It has been well established that the expression of CaBP-9k is mediated with vitamin D response element on its promoter and it regulates the amount of intracellular calcium in order to prevent cell death from reaching the toxicity of free calcium. There is now little doubt that glucocorticoid also decreases CaBP-9k expression in duodenal epithelial cells. In addition, it was reported that the level of CaBP-9k gene in enterocytes is increased in pregnancy when the plasma estradiol concentration is generally associated with a concomitant increase. Although calcium homeostasis was not disturbed in mice lacking the CaBP-9k gene, we found that CaBP-9k has a buffering role of free calcium in the cytosolic environment beyond that of calcium transfer. To expand our knowledge of the biological functions of CaBP-9k, our research has focused on defining the biological significance of intracellular CaBP-9k. Our findings suggest that the CaBP-9k gene is involved in compensatory induction of other calcium transporter genes in duodenal epithelial cells. This article summarizes the findings from recent studies on the expression and the functions of CaBP-9k in the small intestine.

Correlation of Blood Flow of the Preovulatory Follicle to its Diameter and Endocrine Profile in Dairy Buffalo

Blood flow of the preovulatory follicle (POF) wall can be used as a predictor of the quality of POF. Our aim was to determine the correlation of blood flow of POF with the POF diameter, and intra-follicular and plasma concentrations of Insulin-like Growth Factor-I (IGF-1) and oestradiol in dairy buffalo. Nine Murrah buffalo subjected to an ovulation synchronization protocol (Ovsynch) were assessed on day 10 of the protocol for diameter and blood flow of POF, followed by the aspiration of follicle fluid. Prior to follicular aspiration, blood samples were obtained from jugular vein for estimation of IGF-1 and oestradiol. The vascularity of POF was determined (Range: 250-967 pixel(2) ) along with intra-follicular and plasma concentration of IGF-1 (Range: 9.3-31.8ng/ml and 14.7-29.7ng/ml respectively) and oestradiol (Range: 124.2-447.9ng/ml and 0.25-1.05ng/ml respectively). Diameter of the POF was weakly correlated (r=0.21, p<0.01) with blood flow to it. As compared to POF diameter, the blood flow of POF had greater positive correlation with intra-follicular and plasma concentrations of hormones (IGF-1 and oestradiol). A strong positive correlation was recorded between intra-follicular IGF-1 and oestradiol. Also, plasma concentrations of oestradiol and progesterone were negatively correlated In brief, assessment of the blood flow of the POF is a non-invasive and reliable indicator of its functional competence as compared to the POF diameter.

Relationships between Plasma Concentrations of Sex Steroid Hormones and Gonadal Development in the Brown Hagfish,Paramyxine atami

The relationship between sex steroid hormone profiles in plasma and gonadal function in hagfish is poorly understood. In the present study, plasma concentrations of estradiol, testosterone, and progesterone were examined with respect to gonadal development, sexual differences, and possible function of atretic follicles in the brown hagfish, Paramyxine atami, using a time-resolved fluoroimmunoassay. Plasma concentrations of these three hormones were low in juveniles of both sexes. In females, plasma estradiol showed a significant correlation with ovarian development, with the highest concentrations in late vitellogenic adults. Plasma testosterone and progesterone also increased significantly in non-vitellogenic adult females; however, plasma testosterone showed no significant differences among adult females at different ovarian developments, while plasma progesterone was significantly lower in late vitellogenic adults than it was in non-vitellogenic adults. Vitellogenic females that possessed atretic follicles showed significantly lower concentrations of all three hormones than females that only possessed normal follicles. In males, no significant differences were found in plasma estradiol or testosterone levels among groups of different developmental stages of the testis, while plasma progesterone showed a clear inverse relationship with testicular development. Thus, differences were found in plasma sex steroid hormone profiles between male and female P. atami. Moreover, plasma estradiol showed a significant correlation with ovarian development, which suggests that estradiol is involved in the regulation of ovarian development. The present study also revealed that steroid hormone production was strongly suppressed in females that possessed atretic follicles in their ovaries.

Abstract A57: Alcohol consumption and plasma sex steroids in premenopausal women

Abstract Purpose: Alcohol consumption is a consistent risk factor for breast cancer, and evidence suggests premenopausal plasma hormones are associated with breast cancer. In this study, we examined the association between alcohol consumption and plasma sex steroid hormones in premenopausal women. Methods: We assessed the cross-sectional association between alcohol intake and circulating sex steroid concentrations among 2,034 premenopausal women in the Nurses' Health Study II (NHSII). Plasma concentrations of estradiol, estrone, estrone sulfate, testosterone, androstenedione, progesterone, prolactin, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulphate (DHEAS) were measured in samples collected in 1996-99. Estrogens were measured in both the follicular and luteal phases of the menstrual cycle, while androgens were measured in the luteal phase as well as in random samples that were not timed in the menstrual cycle. Average alcohol intake was calculated from semi-quantitative food frequency questionnaires collected in 1995 and 1999. Results: Alcohol consumption was positively association with concentrations of luteal estrone (p-trend&amp;lt;0.0001) and luteal estradiol (p-trend=0.0001). Women who consumed more than 20 grams of alcohol per day, compared with non-drinkers, had higher concentrations of luteal estrone (geometric mean 98.0 vs. 79.9 pg/mL) and luteal estradiol (152.5 vs. 123.3 pg/mL). We did not observe statistically significant associations between alcohol and follicular estrogens, luteal estrone sulfate, testosterone, androstenedione, progesterone, prolactin, DHEA or DHEAS. Conclusion: Alcohol consumption was significantly positively associated with luteal estrogen concentrations, but not with plasma androgen levels, nor estrogens measured in the follicular phase. Thus, luteal estrogen levels may mediate the association between alcohol and breast cancer. Citation Format: Kelly A. Hirko, Susan E. Hankinson, A. Heather Eliassen. Alcohol consumption and plasma sex steroids in premenopausal women. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A57.

Effect of vehicle and route of administration of letrozole on ovarian function in a bovine model

The objective of this study was to determine the effects of vehicle and route of administration of letrozole on ovarian function in sexually mature beef heifers. On Day 3 (Day 0=ovulation), heifers were assigned randomly to four treatment groups and given 1mgkg(-1) letrozole intravenously (iv, n=10) or intramuscularly (im, n=10) or given a placebo iv (control iv, n=5) or im (control im, n=5). The interwave interval was longer in heifers treated with letrozole im than in im and iv controls (11.7±0.30 vs 9.5±0.50 and 10±0.43, respectively; P<0.05). Corpus luteum diameter profiles and plasma progesterone concentrations were greater (P<0.03 and P<0.05, respectively) in heifers treated with letrozole im compared with control im. Plasma oestradiol concentrations were lower in both letrozole-treated groups compared with controls (P≤0.03). Plasma LH concentrations tended to be elevated at the time of wave emergence in heifers treated with letrozole im compared with other groups (group-by-day interaction, P=0.06) and plasma FSH concentrations tended to be greater (P<0.09) in heifers treated with letrozole by either route compared with a single control group. We conclude that intramuscular administration of letrozole in oil is a feasible route and vehicle for the development of a letrozole-based treatment protocol for herd synchronisation in cattle.

Exposure to the endocrine disruptor di(2-ethylhexyl)phthalate affects female reproductive features by altering pulsatile LH secretion

The patterns of growth of preovulatory follicles and corpora lutea, as well as plasma concentrations of estradiol, progesterone and LH were evaluated in sheep exposed to DEHP. There were not found effects on the preovulatory follicular dynamics nor on the ovulatory efficiency between DEHP-exposed and control sheep. However, plasma estradiol concentration was significantly higher in the ewes exposed to DEHP than in the control females (P<0.001). Afterwards, DEHP-exposed ewes had significantly higher plasma progesterone concentration from Day 2 of the luteal phase (P<0.05), although there were no differences between groups in the macro- and microscopic features of the corpora lutea. Analysis of mean basal concentrations of LH showed lower values in DEHP-exposed than in control sheep (0.3±01ng/mL vs. 0.7±0.1; P<0.05). Moreover, the frequency of LH pulses was 0.3pulses/4h, with amplitude of 0.6ng/mL, in the control group; on the other hand, the pulsatile secretion of LH in the DEHP-exposed group was undetectable during the period of sampling.

Oestrus induction in primiparous lactating rabbits by a 48 hours mother-litter separation: endocrine and behavioural responses

Primiparous does express low mating acceptance during lactation and different oestrus induction methods are employed to improve sexual receptivity. The aim of this work was to study the effect of a biostimulation, a 48 h doe-litter separation (DLS), in primiparous lactating rabbits on mating acceptance, external characteristics of the vulva and plasma concentrations of estradiol, testosterone, progesterone and cortisol. Seventy primiparous does from local population were divided on day 1 after kindling into 2 equal groups: control (C, n=35), where does always had free access to the nest-box, and DLS (n=35), where free suckling was adopted, except from day 9 to day 11 post-partum (PP). Litter size was equalised to 6-7 kits. Before mating, blood samples were obtained from 10 does per group on 9th and 11th d post-partum (dpp). The results showed that the DLS treatment improved the mating acceptance on 11th dpp (88.5 vs. 54.2%; P&lt;0.01) and the frequency of red or pink and turgid vulva (54.3 vs. 20%; P&lt;0.01). The sexual receptivity of DLS does depended on the time for which the female was presented to the male: 60% refused mating before opening the nest-box, while 80.9% of them accepted the male after the nursing episode. Plasma levels of estradiol, testosterone and progesterone in DLS group rose from 9th to 11th dpp (+44.4; +59.2 and +82%, respectively; P&lt;0.01) compared to C group (+6.7; –3.9 and +33.4%, respectively; P&gt;0.05). In contrast, cortisol plasma levels were not affected by the DLS treatment (–12.4 and –14.4% for control and DLS group; P&gt;0.05). At day 11 PP, higher plasma E2 and P4 levels were described in DLS in comparison to C, although no significant difference was found, while plasma testosterone concentrations tended to be higher in DLS (165.5±27.1 vs. 114.9±31.9 pg/mL, for DLS and C, respectively; P=0.075). In summary, the 48 h doe-litter-separation acted as an efficient oestrus inductor in primiparous lactating rabbits. Insemination of biostimulated does must occur after the 1st suckling episode following the separation. This biostimulation method did not modify cortisol secretion of the rabbit doe.

Effects of high somatic cell counts in milk on reproductive hormones and oestrus behaviour in dairy cows with special reference to those with concurrent lameness

The present investigation aims to establish the reason(s) why dairy cows with high somatic cell counts (SCCs; >100,000 cells/ml) are less fertile than cows with low SCCs alone. The objective of Study One was to determine whether differences in steroid hormone profiles could explain the low incidence of ovulation in cows with combined High SCC and lameness. Between 30 and 80 days post-partum, animals were scored for SCC and lameness and three groups were formed: Healthy (n=22), High SCC alone (n=12) or High SCC + Lame (n=9). The ovarian follicular phases of all cows were synchronised by administering gonadotrophin releasing hormone (GnRH) followed seven days later by prostaglandin F2alpha (PG). Milk samples were collected daily throughout the entire study period; twice daily during the follicular phase, blood samples were taken and the ovaries were monitored using ultrasonography. Progesterone concentrations were similar in all three groups during each of five specific time periods, i.e. throughout the five days before PG injection, the peri-ovulatory period, on Day 5 and on Day 7, and during the mid luteal phase 12–17 days after ovulation (P>0.13). Mean plasma oestradiol concentrations monitored every 12h during the 36h period before ovulation were similar in all groups (Healthy, 2.80±0.30pg/ml; High SCC alone, 3.82±0.48pg/ml; High SCC+Lame 2.94±0.51pg/ml; P=0.175). The objective of Study Two was to establish whether cows with High SCC (scored and synchronised as above) display different behaviours, especially the intensity and timing of oestrus. Intervals from PG to the onset of oestrus or to the first stand-to-be-mounted (STBM) were longer for the High SCC cows than the Low SCC animals (n=8 and 20; P=0.011 and 0.002, respectively). Also, cows with High SCC tended to have a less intense oestrus and a lower maximum oestrus score per 30-min period than Low SCC cows (P=0.063 and 0.066, respectively). In conclusion, High SCC±lameness did not affect progesterone or twice daily oestradiol profiles but the onset of oestrus was delayed and oestrus tended to be less intense in cows with High SCC. These factors could explain low fertility associated with High SCC.

Prolific strains of Barbarine sheep are characterized by increased ovulation rate due to extended period of ovulatory follicle recruitment and co-dominance effects

Preovulatory follicle dynamics and plasma oestradiol around the time of onset of oestrus as well as ovulation rate were assessed, during non-breeding season, in prolific (W; n=20) and non prolific (AB; n=20) strains of the Barbarine sheep. Oestrus cycles were synchronized with progestagen sponges for 14 days followed by introduction of rams. Transrectal ultrasonographic monitoring of the ovaries was carried out from the day of pessaries removal up to oestrous exhibition. Blood samples were collected every 4h and were analyzed for plasma concentrations of oestradiol by radioimmunoassay. Laparoscopy was performed 11 days after introduction of rams to assess number of corpora lutea (CL). Results indicate that along the first 5 days after introduction of rams, 20 and 14 ewes of respectively the AB and W ewes exhibited oestrus (P<0.01). Ewes of the W strain had more medium (3.5–5.4mm) follicles than AB ones during the follicular phase; the difference being significant (P<0.01) 24h before oestrus. The number of medium follicles prior to oestrus changed little in AB ewes but declined rapidly from 5.8±0.7 to 4.0±0.6 in W females (P<0.05). Differences in medium follicles between strains were not reflected in the number of large (≥5.5mm) or the growing large follicles during the follicular phase. Around oestrus, plasma oestradiol concentrations were higher for W in comparison to AB ewes (22.3±12.6 vs. 11.8±6.2pg/ml; P<0.01) and mean ovulation rates were 1.8±0.8 and 1.1±0.3 for respectively W and AB ewes (P<0.01). In conclusion, the increased ovulation rate in the W strain is related to an extended period of follicle recruitment with appearance of co-dominance effects.

Androgen levels during adjuvant endocrine therapy in postmenopausal breast cancer patients

Objective To investigate plasma steroid hormone levels in postmenopausal breast cancer patients with and without adjuvant endocrine therapy and in healthy postmenopausal women.Methods Steroid hormone levels in postmenopausal breast cancer patients treated with aromatase inhibitors (n = 32) were compared with breast cancer patients treated with tamoxifen (n = 34), breast cancer patients without adjuvant endocrine therapy (n = 15), and healthy postmenopausal women (n = 56). Pregnenolone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol, cortisone, dehydroepiandrosterone (DHEA), androstenedione, total testosterone, dihydrotestosterone, estrone and estradiol were measured using liquid chromatography–tandem mass spectrometry. Sex hormone binding globulin was measured by solid-phase chemiluminescent immunometric assays, and the free androgen index was calculated.Results Aromatase inhibitor users did not differ in dihydrotestosterone, total testosterone, androstenedione, DHEA, or free androgen index levels from healthy controls or untreated breast cancer patients. The highest total testosterone levels were found in tamoxifen-treated women, who had significantly higher plasma concentrations than both women treated with aromatase inhibitors and breast cancer patients without adjuvant treatment. Concentrations of cortisol and cortisone were significantly greater in aromatase inhibitor users as well as tamoxifen users, in comparison with healthy controls and untreated breast cancer patients. Aromatase inhibitor users had lower estrone and estradiol plasma concentrations than all other groups.Conclusion Adjuvant treatment with aromatase inhibitors or tamoxifen was associated with increased cortisol and cortisone plasma concentrations as well as decreased estradiol concentrations. Androgen levels were elevated in tamoxifen-treated women but not in aromatase inhibitor users.

Changes in mammary secretory tissue during lactation in ovariectomized dairy cows

In dairy animals, the milk yield (MY) changes during a lactation and is influenced by several physiological, livestock management and environmental factors. The MY produced by a mammary gland depends on synthetic activity of mammary epithelial cells (MECs) as well as MEC number and mammary secretory tissue organization. It has been suggested that ovarian steroids (estradiol and progesterone) have a negative effect on MY in lactating cows. In a previous study, we showed that the suppression of ovarian secretions by an ovariectomy improved lactation persistency in dairy cows. Here we were interested in the effects of ovariectomy on plasma estradiol and progesterone concentrations and on changes that occur in mammary secretory tissue during lactation. We demonstrated that the ovariectomy of lactating cows at the time of the lactation peak induced a rapid and dramatic drop in plasma progesterone and a smaller reduction in plasma estradiol. Interestingly, the study of the changes in mammary secretory tissue over time revealed that the improvement of MY measured in the ovariectomized cows was associated with a limited increase in estradiol receptivity in MECs, a reduced mammary tissue remodeling and reduced blood protein concentration in milk, in late lactation. These results suggest that ovarian secretions, particularly estradiol and progesterone, act to enhance processes for mammary gland involution in late-lactating dairy cows.

Regulation of the hyaluronan system in ovine endometrium by ovarian steroids

In this study, we investigated steroid regulation of the hyaluronan (HA) system in ovine endometrium including HA synthases (HAS), hyaluronidases, and HA receptor-CD44 using 30 adult Welsh Mountain ewes. Eight ewes were kept intact and synchronized to estrous (day 0). Intact ewes were killed on day 9 (luteal phase; LUT; n=5) and day 16 (follicular phase; FOL; n=3). The remaining ewes (n=22) were ovariectomized and then treated (i.m.) with vehicle (n=6) or progesterone (n=8) for 10 days, or estrogen and progesterone for 3 days followed by 7 days of progesterone alone (n=8). Estradiol and progesterone concentrations in plasma correlated with the stage of estrous or steroid treatment. Our results showed trends (P<0.1) and statistically significant effects (P<0.05, by t-test) indicating that LUT had lower HAS1 and HAS2 and higher HAS3 and CD44 mRNA expression compared with FOL. This was reflected in immunostaining of the corresponding HAS proteins. Similarly, in ovariectomized ewes, progesterone decreased HAS1 and HAS2 and increased HAS3 and CD44, whereas estradiol tended to increase HAS2 and decrease CD44. Sometimes, HAS mRNA expression did not follow the same trend observed in the intact animals or the protein expression. HA and its associated genes and receptors were regulated by the steroids. In conclusion, these results show that the level of HA production and the molecular weight of HA in the endometrium are regulated by ovarian steroids through differential expression of different HAS both at the gene and at the protein levels.