Plasma Estradiol Concentrations Research Articles

Longitudinal changes in plasma sex hormone concentrations correlate with changes in CT-measured regional adiposity among Japanese American men over 10years.

Ageing in male adults is typically accompanied by adiposity accumulation and changes in circulating sex hormone concentrations. We hypothesized that an ageing-associated increase in oestrogens and decrease in androgens would correlate with an increase in adiposity. 10-year prospective, observational study. A total of 190, community-dwelling men in the Japanese American Community Diabetes Study. At 0 and 10years, CT scanning quantified intra-abdominal fat (IAF) and subcutaneous fat (SCF) areas while plasma concentrations of oestradiol, oestrone, testosterone and dihydrotestosterone were measured by liquid chromatography-tandem-mass spectrometry at each time point. Multivariate linear regression analyses assessed correlations between 10-year changes in hormone concentrations and IAF or SCF, adjusting for age and baseline fat depot area. Participants were middle-aged [median 54.8 years, interquartile range (IQR) 39.9-62.8] men and mostly overweight by Asian criterion (median BMI 24.9, IQR 23.3-27.1) and with few exceptions had normal sex-steroid concentrations. Median oestradiol and dihydrotestosterone did not change significantly between 0 and 10years (P=.084 and P=.596, respectively) while median oestrone increased (P<.001) and testosterone decreased (P<.001). Median IAF and SCF increased from 0 to 10years (both P<.001). In multivariate analyses, change in oestrone positively correlated (P=.019) while change in testosterone (P=.003) and dihydrotestosterone (P=.014) negatively correlated with change in IAF. Plasma oestradiol and oestrone positively correlated with change in SCF (P=.041 and P=.030, respectively) while testosterone (P=.031) negatively correlated in multivariate analysis. Among 190 community-dwelling, Japanese American men, increases in IAF were associated with decreases in plasma androgens and increases in plasma oestrone, but not oestradiol, at 10years. Further research is necessary to understand whether changing hormone concentrations are causally related to changes in regional adiposity or whether the reverse is true.

Plasma estradiol and progesterone concentrations during the female reproductive cycle in a highly placentotrophic viviparous lizard, Mabuya sp.

The neotropical genus Mabuya are obligate placentotrophic viviparous lizards, which have a short vitellogenesis that produces microlecithal oocytes and a prolonged time of gestation (9 to 10 months). The hormonal control of female reproductive activity during follicular growth and pregnancy has not been studied, although it is known that the corpus luteum can produce progesterone, but regresses early in pregnancy, being replaced in this function by the placenta. Through enzyme immunoassay (EIA) we measured the plasma concentrations of estradiol (E2) and progesterone (P4) in females of a population of Mabuya sp at different stages of their reproductive cycle. Previously, we confirmed the presence of P4 in plasma by high-performance liquid chromatography methods with diode-array detector ultraviolet (HPLC-DAD-UV). The average concentration values of E2 and P4 were compared among reproductive stages and their dynamics were related to what is known in other oviparous and viviparous amniotes. The plasma E2 concentrations of Mabuya sp. are below the levels found in other viviparous reptiles, probably related to the substantial reduction of its follicular growth phase. Its highest concentration was detected during vitellogenesis, related to its function in the growth and maturation of the ovarian follicles and oviduct preparation for pregnancy; lower levels were observed during pregnancy, but they increase at the end when a new vitellogenesis event begins and massive placental maternal-fetal nutrient transfer occurs. High concentrations of P4 were found during pregnancy, related to its function in the maintenance of the developing embryos within the oviduct. The highest levels of P4 were found at early gestation, then they descend from mid-gestation to the end of gestation. Although some characteristics of hormonal control related to the high level of placentotrophy were observed in this species, the changes in plasma sex steroid concentrations during the reproductive cycle in females of Mabuya sp. follow patterns seen in other viviparous amniotes.

Behavioural differences between breeding and nonbreeding pairs of protandry monogamous false clown anemonefish Amphiprion ocellaris

Anemonefishes are some of the most popular marine ornamental fishes. Due to the adverse impacts of commercial fishing on the wild populations of anemonefishes, a more suitable and efficient captive breeding programme must be promoted. In the wild, anemonefishes are protandrous sex-changing fish, but when two immature individuals with ambisexual gonads are raised together in captivity, the two differentiate directly into a male and a female, to form a breeding pair. However, not all the formed pairs spawn, explaining the great care required in captive breeding. This behaviour appears to be counter-adaptative, as anemonefish social groups form randomly in the wild, and such phenomenon would disturb their breeding success. This study evaluated the behavioural and physiological differences between breeding and nonbreeding pairs of false clown anemonefish Amphiprion ocellaris under captive conditions. Behavioural observations revealed that nonbreeding females monopolized the shelter provided, whereas breeding females allowed breeding males to use the shelter and the pair frequently stayed together in the shelter. Both nonbreeding and breeding females possessed mature ovarian tissue and similar level of plasma estradiol concentrations, but nonbreeding males had a smaller amount of testicular tissue and lower plasma 11-ketotestosterone levels compared to breeding males.

Administration of aromatase inhibitor MPV-2213ad to blue fox vixens (Vulpes lagopus) as a model for contraception in female dogs

The interest in non-surgical approaches to contraception and fertility control in female dogs has increased in recent years. In this study the effect of an aromatase inhibitor (finrozole) was evaluated in fur production animals, farmed blue fox vixens, as a model for contraception in bitches. A total of 80 vixens were divided into 4 groups, receiving orally placebo (A) or finrozole 0.5 mg/kg (B), 3.5 mg/kg (C) or 24.5 mg/kg (D) for 21 consecutive days beginning in the pre-ovulatory period of heat. Monitoring of the vixens included clinical signs of heat, measurement of vaginal electrical resistance (VER) as well as oestradiol and progesterone concentrations in plasma. The approximate relation of the start of treatment to ovulation varied from 11 days before to one day after ovulation provided that the LH peak occurred 0.5–2 days before the VER peak and ovulation was then estimated to occur 2 days after the LH peak. Seventy vixens were artificially inseminated within 8 h after a 50 Ω decline in vaginal electrical resistance was detected. Ten vixens were not inseminated. Pregnancy was confirmed by transabdominal ultrasound examination and birth of cubs was recorded. The pregnancy rates in the groups were 89.5% (A), 81.3% (B), 55.6% (C) and 52.9% (D). The average number of live born pups in the four groups was 9.4 (A), 7.0 (B), 5.8 (C), and 3.8 (D), respectively. No deleterious effects (for instance malformations) of finrozole on pups could be verified. The administration of finrozole did not have a significant effect on oestradiol parameters and VER values in vixens. Progesterone values were significantly higher in treatment groups compared with the placebo group. The results indicate that pregnancy could be avoided by finrozole provided that doses of ≥3.5 mg/kg were used and the treatment was initiated at least four days before the day of artificial insemination. This corresponds with two to six days before ovulation provided that the LH peak occurred 0.5–2 days before the VER peak and that ovulation then occurred in average 2 days after the LH peak.

The effect of diet therapy on the anthropometric and metabolic parameters in women with infertility and obesity

Aim: to monitor the anthropometric, hormonal and metabolic parameters in women of reproductive age with infertility and grade I gluteofemoral obesity during treatment with a balanced hypocaloric diet. Materials and methods . The study included 23 infertile women of reproductive age. All patients were prescribed a balanced, low-calorie diet (1200 kcal/day), exercise, and behavioral therapy. The anthropometric, metabolic and hormonal parameters were determined before and 12 months after the treatment. We measured the levels of leptin, total cholesterol, triglycerides, triglycerides, high-density and low-density lipoprotein cholesterol (HDL cholesterol and LDL cholesterol), fasting glycose. Following the measurements, the atherogenic and insulin resistance indices were calculated. In addition, the plasma concentrations of luteinizing hormone, follicle-stimulating hormone, prolactin, estrone, estradiol, testosterone, progesterone, and immunoreactive insulin were measured. Results. Twenty patients completed the study. A decrease in body weight (by average of 10.58 ± 5.70 kg) was found in 87 % of patients; in parallel, the body mass index decreased from 32.53 ± 1.40 to 28.55 ± 2.50 kg/m2 (p < 0.001). The decrease in body weight was accompanied by a statistically significant decrease in the levels of leptin (p < 0.001), estrone (p = 0.049), estradiol (p = 0.032), total cholesterol (p < 0.001), triglycerides (p = 0.004), LDL cholesterol (p = 0.001), fasting glycose (p < 0.001), insulin resistance index (p = 0.002), atherogenic index (p < 0.001) and an increase in the level of progesterone (p = 0.030). The ovulatory menstrual cycle was restored in all women (p = 0.007); within one year, wanted pregnancy occurred in 1 woman. Conclusion. The use of a low-calorie diet for 12 months in infertile women with grade I gluteofemoral obesity leads to normalization of metabolic parameters, weight loss and, the restoration of the ovulatory menstrual cycle in 100 % of cases.

Pharmacogenetic interactions between antiretroviral drugs and vaginally administered hormonal contraceptives

In AIDS Clinical Trials Group study A5316, efavirenz lowered plasma concentrations of etonogestrel and ethinyl estradiol, given as a vaginal ring, while atazanavir/ritonavir increased etonogestrel and lowered ethinyl estradiol concentrations. We characterized the pharmacogenetics of these interactions. In A5316, women with HIV enrolled into control (no antiretrovirals), efavirenz [600 mg daily with nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)], and atazanavir/ritonavir (300/100 mg daily with NRTIs) groups. On day 0, a vaginal ring was inserted, releasing etonogestrel/ethinyl estradiol 120/15 μg/day. Intensive plasma sampling for antiretrovirals was obtained on days 0 and 21, and single samples for etonogestrel and ethinyl estradiol on days 7, 14, and 21. Seventeen genetic polymorphisms were analyzed. The 72 participants in this analysis included 25, 24 and 23 in the control, efavirenz, and atazanavir/ritonavir groups, respectively. At day 21 in the efavirenz group, CYP2B6 genotype was associated with increased plasma efavirenz exposure (P = 3.2 × 10), decreased plasma concentrations of etonogestrel (P = 1.7 × 10), and decreased ethinyl estradiol (P = 6.7 × 10). Compared to controls, efavirenz reduced median etonogestrel concentrations by at least 93% in CYP2B6 slow metabolizers versus approximately 75% in normal and intermediate metabolizers. Efavirenz reduced median ethinyl estradiol concentrations by 75% in CYP2B6 slow metabolizers versus approximately 41% in normal and intermediate metabolizers. CYP2B6 slow metabolizer genotype worsens the pharmacokinetic interaction of efavirenz with hormonal contraceptives administered by vaginal ring. Efavirenz dose reduction in CYP2B6 slow metabolizers may reduce, but will likely not eliminate, this interaction.

Estrogen Replacement Improves Mesenteric Arterial Relaxation in UC Davis Pre‐diabetic Rats: Possible Involvement of Estrogen Receptor Beta

The risk of cardiovascular diseases (CVD) is lower in premenopausal women compared to men, and this lower risk is related to the presumptive cardioprotective effects of female sex hormones, estrogen in particular. However, premenopausal women may lose this protection with the onset of menopause and/or when they become diabetic. Little is known about the vascular function in presence or absence of estrogen at the early stage of diabetes.The objective of this study was to investigate the effects of 17β‐estradiol (E2) replacement on mesenteric arterial (MA) function in ovariectomized (ovex) UC Davis type 2 diabetes mellitus (UCD‐T2DM) rats at the pre‐diabetic stage. MA were obtained from four groups of ovex rats implanted with a subcutaneous pellet for 45 days: (1) Control (Ctrl), ovex + placebo, (2) Ctrl, ovex + E2 (1.5mg/pellet), (3) pre‐diabetic, ovex + placebo, (4) pre‐diabetic, ovex + E2. Endothelium‐dependent vasodilation (EDV) to acetylcholine (ACh, 10−8 to 10−5 M) in MA were measured before and after indomethacin (Indo, 10μM), a cyclooxygenase (COX) inhibitor; followed by addition of L‐NAME (200μM), a nitric oxide synthase (NOS) inhibitor. The MA expression of estrogen receptors (ERs) and plasma E2 concentration were determined by Western blotting and ELISA assay, respectively.E2 treatment significantly increased plasma estradiol concentration in both Ctrl and Prediabetic groups. Analysis of ERs showed a higher expression of ER‐beta only in E2‐treated prediabetic group. ACh responses were similar in Ctrl groups, regardless of E2 replacement. ACh induced relaxation was, however, markedly reduced in MA of placebo treated pre‐diabetic group compared with other groups. Treatment of pre‐diabetic with E2 enhanced relaxation to the same level as those from Ctrl rats. Blocking of both COX and NOS completely abolished the relaxation responses to ACh in pre‐diabetic groups, regardless of E2 replacement, indicating no contribution of EDHF‐type relaxation in these groups. However, the added effect of L‐NAME, in presence of Indo, in blocking ACh‐mediated vasodilation was much more prominent in E2‐treated prediabetic group when compared with placebo treated group, indicating an enhanced role of NO. On the other hand, both NO and EDHF remained important for EDV in Ctrl groups. Addition of L‐NAME, however, caused a much smaller reduction of EDV in E2 treated than in placebo treated arteries, suggesting EDHF is the predominant mediator of mesenteric vasorelaxation in this groups.Here, we show that EDV is impaired at pre‐diabetic stage, may be due to loss of EDHF. E2 treatment restores EDV in MA of pre‐diabetic group, possibly via elevated contribution of NO‐mediated relaxation by increased E2 signaling (via ER beta) in this group. The role of ER alpha remains to be investigated.Support or Funding InformationSupported by NHLBI.

Conception Rate and Reproductive Hormone Secretion in Holstein Cows Immunized against Inhibin and Subjected to the Ovsynch Protocol.

Simple SummaryIn recent decades, conception rates in lactating dairy cows have dramatically decreased, and improving the conception rate has become a major challenge in dairy cow reproduction. Various Ovsynch protocols have been developed to aid in the resumption of ovarian follicular activity for timely breeding in post-partum cows. However, the effect of Ovsynch protocols on improving the conception rate is unsatisfactory. In addition, immunization against inhibin was reported to improve the fertility of domestic animals. Thus, a novel reproductive technique combining immunization against inhibin and the widely used Ovsynch protocol was proposed and tested in this study. Our results showed that immunization against inhibin has the potential to improve conception rates in cows, but also compromised luteal function. According to these results, additional luteal-stimulating treatments are suggested to further improve cow fertility based on immunization and the Ovsynch protocol.This study was conducted to investigate the feasibility of improving fertility in dairy cows via immunization against inhibin. Thirty-two cows were divided into Control (n = 11), Low-dose (n = 10) and High-dose (n = 11) groups. The High-dose and Low-dose cows were treated with 1 and 0.5 mg of the inhibin immunogen, respectively. All the cows were subjected to the Ovsynch protocol from the day of antigen administration and were artificially inseminated. Blood samples were serially collected over a 24-day period from the start of the Ovsynch protocol to 14 days after insemination. The results showed that immunization against inhibin dose-dependently increased the plasma concentrations of follicle-stimulating hormone (FSH), estradiol (E2), and activin A, but decreased progesterone (P4) concentrations in the luteal phase. Immunization also increased the plasma interferon (IFN)-τ concentrations in pregnant cows on day 14 after initial insemination. The conception rates in High-dose (45.5%) and Low-dose (40%) cows marginally increased compared to that in Control cows (27.3%), but the increases were not significant (p > 0.05). In conclusion, a single immunization against inhibin has the potential to improve conception rates, despite impaired luteal development. To further improve the reproductive performance of dairy cows, additional luteal-stimulating treatments are suggested in combination with immunization against inhibin and Ovsynch techniques.

Research and development of a silicone letrozole-releasing device to control reproduction in cattle

Two experiments were conducted to test the effectiveness of a silicone matrix as an intravaginal drug delivery device for letrozole, an aromatase inhibitor used for synchronization protocols in cattle. A wax dip-coat formulation of the intravaginal device used in previous studies was effective in releasing letrozole but was cumbersome to manufacture and deploy, resulting in unwanted variation in drug delivery and circulating concentrations of letrozole. In Experiment 1, a 3 × 3 design was used to test the release kinetics of letrozole from silicone in vitro. Silicone was mixed with 3 different letrozole drug loads (5%, 10%, 15%) and 3 different mineral oil loads (5%, 10%, 15%), and letrozole release into 62.5% ethanol was compared with the wax dip-coat formulation (positive control) by UV spectrophotometry. Letrozole was released from silicone in a dose-dependent manner, with no effect of mineral oil. Release kinetics were then examined in vivo (Experiment 2) in nulliparous beef heifers assigned randomly to six groups (n = 6/group) and given either a large surface area (LSA) with 5% or 15% drug load, a standard surface area (SSA) intravaginal silicone device impregnated with 10% or 15% drug load, a wax dip-coat device (positive control), or a blank device (negative control). Devices were inserted on Day 3 (Day 0 = ovulation) until Day 11. Blood samples were collected at 0, 30 min, 1, 2, 3, 4, 6, 8, 10, 12, and 24 h, and twice daily until Day 11 to determine letrozole plasma concentrations by LC-MS/MS and estradiol plasma concentrations by radioimmunoassay The ovaries were examined once daily from Day 3–13 by ultrasonography to determine follicular and luteal responses to treatment. Letrozole plasma concentrations were higher in heifers given a device with an LSA vs SSA (P < 0.05). Plasma concentrations of estradiol decreased the most in heifers given the 15% LSA device (P = 0.06). The interval between emergence of successive follicular waves was longest (P < 0.05) in the positive control and the 15% LSA groups. As well, the diameter profiles of the dominant follicle and the corpus luteum were largest (P < 0.01) in the positive control and 15% LSA groups. In conclusion, letrozole was released from a silicone matrix in vitro in a dose-dependent manner, and the 15% LSA devices achieved target effects on ovarian function. Results may be used to manufacture a silicone intravaginal device for delivering aromatase inhibitors in a novel synchronization protocol for cattle.

Endogenous sex hormones and colorectal cancer survival among men and women.

Although previous studies have suggested a potential role of sex hormones in the etiology of colorectal cancer (CRC), no study has yet examined the associations between circulating sex hormones and survival among CRC patients. We prospectively assessed the associations of prediagnostic plasma concentrations of estrone, estradiol, free estradiol, testosterone, free testosterone and sex hormone-binding globulin (SHBG) with CRC-specific and overall mortality among 609 CRC patients (370 men and 239 postmenopausal women not taking hormone therapy at blood collection) from four U.S. cohorts. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard regression. We identified 174 deaths (83 CRC-specific deaths) in men and 106 deaths (70 CRC-specific deaths) in women. In men, higher circulating level of free testosterone was associated with lower risk of overall (the highest vs. lowest tertiles, HR = 0.66, 95% CI, 0.45-0.99, ptrend = 0.04) and possibly CRC-specific mortality (HR = 0.73, 95% CI, 0.41-1.29, ptrend = 0.27). We generally observed nonsignificant inverse associations for other sex steroids, and a positive association for SHBG with CRC-specific mortality among male patients. In women, however, we found a suggestive positive association of estrone with overall (HR = 1.54, 95% CI, 0.92-2.60, ptrend = 0.11) and CRC-specific mortality (HR = 1.96, 95% CI, 1.01-3.84, ptrend = 0.06). Total estradiol, free estradiol and free testosterone were generally suggestively associated with higher risk of mortality among female patients, although not statistically significant. These findings implicated a potential role of endogenous sex hormones in CRC prognosis, which warrant further investigation.

Increased number of large non-atretic follicles and co-dominance effects account for high litter sizes in Bonga sheep.

To understand the ovarian basis for prolificacy of Bonga sheep, a total of 31 ewes were selected based on litter size (LS) records and divided into two groups: High Prolificacy (HP) (n=20) with LS≥2 and Low Prolificacy (LP) (n=11) with LS=1. At a synchronized estrus, follicular dynamics were determined using transrectal ultrasonography. Plasma estradiol concentrations were also monitored. In total 27 ewes were observed in estrus being 9/11 LP (82%) and 18/20 HP (90%). On the day of estrus (day 0), the mean number of large follicles was higher (p<.05) in HP (1.78±0.19) than in LP (1.0±0.28) ewes. Prior to estrus, more (p<.05) medium follicles were visible for HP compared to LP ewes. Plasma estradiol concentrations were higher in HP compared to LP ewes (18.91±0.41 vs. 14.51±0.65pg/ml; p<.05) and similarly was ovulation number (2.3±0.15 vs. 1.28±0. 14; p<.05). Higher ovulation rates and litter size in Bonga sheep are evidenced by the previous presence of more large follicles and the existence of co-dominance effects as most likely medium follicles are selected to ovulate.

Adrenomedullin Rescues Testicular Steroidogenesis of Leydig Cells by Suppressing TGF-β1 &lt;i&gt;via&lt;/i&gt; PI3K/Akt-Dependent Activation of GSK-3β/β-Catenin Signaling Pathway

Backgroud: Lipopolysaccharide (LPS) exposure can induce Leydig cell dysfunction. This study aims to investigate whether adrenomedullin (ADM) rescues the steroidogenic functions of Leydig cells by suppressing TGF-β1 via PI3K/Akt/ GSK-3β/β-catenin signaling. Methods: Rats were given LPS and injected with an adeno-associated virus vector that expressed ADM (Ad-ADM). Plasma concentrations of testosterone and estradiol were measured. Testes were collected and analyzed by gene expression profiling, western blot and immunofluorescence staining. Primary Leydig cells were treated with various concentrations of LPS and ADM. Cell viability and proliferation and medium concentrations of testosterone and estradiol were detected. Gene expression and protein l evels were detected for steroidogenic enzymes, TGF-β1, PI3K, Akt, GSK-3β and β-catenin. Role of ADM in the regulation of TGF-β1 promoter was confirmed by ChIP and Co-IP. Finding: ADM reversed the decreased number of Leydig cells and plasma concentrations of testosterone and estradiol by rescuing the expression of SF-1, 17β-HSD, LRH1, CYP19, StAR, P450scc, 3β-HSD and CYP17. ADM inhibited the LPS-induced cytotoxicity and reversed the cell proliferation by rescuing the expression of Ki-67. ADM also rescued the expression of SF-1, 17β-HSD, LRH1, CYP19, StAR, P450scc, 3β-HSD and CYP17 and the medium concentrations of testosterone and estradiol in LPS-induced Leydig cells. ADM ameliorated LPS-induced TGF-β1 expression in LPS-exposed Leydig cells. ADM enhanced the phosphorylation of PI3K, Akt and GSK-3β but reduced the activation of β-catenin which interacted with TCF4 and then bound to TGF-β1 gene promoter. Interpretation: ADM may rescue the steroidogenic functions of Leydig cells by suppressing TGF-β1 via the PI3K/Akt/GSK-3β/β-catenin signaling. Funding Statement: This study was supported by the National Science Foundation of China, Beijing, China (Grant Nos.: 81402100, 81401190), Natural Science Foundation of Hunan Province, China (Grant Nos.: 2019JJ40269, 2020JJ4542), Foundation for “Young Medical Talents” of Jiangsu Province, China (Grant No.: QNRC2016840), and Key Guidance Project of University of South China, China (Grant No.: USCKF201902K01). Declaration of Interests: The authors declare no competing financial interests with regard to the publication of this paper. Ethics Approval Statement: Procedures involving rats were approved by the Local Ethics Committee for the Care and Use of Laboratory Animals of University of South China and were conducted in accordance with the national guidelines and protocols of the National Institutes of Health.

Influence of ipsilateral coexistence of the first wave dominant follicle and corpus luteum on ovarian dynamics and plasma sex steroid hormone concentrations in lactating dairy cows treated with human chorionic gonadotropin.

We examined the effect of human chorionic gonadotropin (hCG) treatment 5 days after estrus on ovarian dynamics and plasma progesterone (P4) and estradiol (E2) concentrations when the first-wave dominant follicle (DF) was ipsilateral or contralateral to the corpus luteum (CL) in lactating dairy cows. Seventy cows were divided into two groups: (1) ipsilateral group (IG; n = 37), in which the first-wave DF was ipsilateral to the CL, and (2) contralateral group (CG; n = 33), in which the first-wave DF was contralateral to the CL. IG and CG were further subdivided into two groups: non-treatment group (IG, n = 18; CG, n = 19), and hCG treatment group: administrated 1500 IU of hCG 5 days after estrus (IG, n = 19; CG, n = 14). Blood sampling and ovarian examination were performed at 3, 5, 7, 9, 11, and 13 days after estrus. Mean diameter of the first-wave DF on Day 9 tended (P = 0.067) to be larger in IG than in CG in the non-treatment group. Mean diameter of CL and plasma P4 and E2 concentrations did not differ between IG and CG in the non-treatment and hCG treatment groups. Accessory CL development did not differ between IG and CG in the hCG treatment group. Our findings indicate that CL development and plasma P4 and E2 concentrations were not affected by the existence of the first-wave DF; however, first-wave DF development was affected by the existence of a CL in the same ovary.

Effect of paracetamol treatment on maternal care and reproductive outcomes in female rat offspring.

Paracetamol (PAR) is one of the most commonly used drugs by pregnant women because it is considered safe for the mother and fetus. However, PAR is transferred into breast milk and crosses the blood-placental barrier, being present in the progeny during important stages of development. Intrauterine exposure to PAR may decrease the anogenital distance and follicle reserve in female rodent offspring. Therefore, the aim of the present study was to evaluate whether maternal PAR treatment altered the reproductive behaviour of dams and the sexual development of female rat offspring. Pregnant Wistar rats were gavaged daily with 350mg kg-1 day-1 PAR or water during gestation (from Gestation Day (GD) 6 until delivery) or during gestation and lactation (from GD6 until weaning). Maternal PAR treatment had maternal effects (increased grooming behaviour), and resulted in impaired sexual behaviour, decreased follicle reserve and increased plasma oestradiol concentrations in female offspring.

156 Oestrus response, corpus luteum function, and pregnancy rates following aromatase inhibitor treatment in beef heifers

In a previous study involving the use of the aromatase inhibitor letrozole to synchronise ovulation, incomplete luteolysis appeared to confound the synchronising effect in letrozole-treated heifers. Experiments were done to determine whether letrozole treatment interferes with luteolysis and affects the timing of oestrus (Experiment 1) and whether pregnancy rate is affected by the stage of the oestrous cycle during which letrozole treatment is initiated (Experiment 2). In Experiment 1, Hereford heifers were fitted with a HeatWatch sensor and given prostaglandin F2α (PGF2α). Ovulation (Day 0) was determined by daily ultrasonography, and on Day 3 heifers were given an intravaginal letrozole-releasing device or a sham device for 4 days (n=16 per group). Half of the heifers in each group were given PGF2α on Day 7 (PGF 1×) or on Day 7 and 7.5 (PGF 2×). Ultrasonography and blood sampling were done daily from device insertion to removal, every 12h for 72h following PGF2α and daily for 14 days following ovulation. In Experiment 2, heifers were randomly assigned to three groups (n=10-11 per group) in which a 4-day letrozole-releasing device treatment was initiated during metoestrus (Days 0-2), diestrus (Days 7-9), or pro-oestrus (Days 15-17). Prostaglandin F2α was given at device removal and again 12h later. Heifers were inseminated with frozen-thawed semen and given gonadotrophin-releasing hormone 66h after device removal. Ultrasonography and blood sampling were done twice daily from device removal until ovulation. End points examined included dominant follicle and corpus luteum (CL) diameters, onset of oestrus, and plasma concentrations of oestradiol determined by radioimmunoassay. Nominal data were compared using GENMOD, analysis of variance, or mixed model for repeated-measures and were expressed as means±s.e.m. Proportional data were analysed using chi-square. In Experiment 1, no main effects or interactions were detected between device or PGF treatment for onset of oestrus following PGF2α (overall 60.0±2.5h) or CL diameter profiles during luteolysis. Residual variation was reduced in the timing of the first PGF to ovulation in the PGF 2× group versus the PGF 1× group (5.6±2.2h vs. 15.2±3.2 h; P&amp;lt;0.01). The CL diameter following ovulation was greater in the PGF 2× group compared with the PGF 1× group (P=0.03). Circulating plasma oestradiol during treatment was greater (P=0.04) in both the PGF 1× and sham groups. In Experiment 2, a greater proportion of heifers in the pro-oestrus group ovulated ≤24h after device withdrawal compared with the metoestrus and diestrus groups combined (6/11 vs. 0/22, respectively; P&amp;lt;0.05). Pregnancy rate tended to be greater in the metoestrus group than in the diestrus group (10/11 vs. 6/10; P=0.08), and pregnancy rate in both groups was greater than that in the pro-oestrus group (0/11; P&amp;lt;0.05). In conclusion, letrozole treatment did not interfere with luteolysis, and PGF2α given 2× at a 12-h interval on Day 7 after ovulation decreased variance in the timing to ovulation. Treatment initiated during metoestrus and diestrus yielded greater pregnancy rates than that started during pro-oestrus and warrants efficacy testing in a large fixed-time AI field trial. This research was supported by Alberta Agriculture and Forestry and by Dechra.

A predictive model to diagnose pregnancy in guanacos (Lama guanicoe) using non-invasive methods

Pregnancy status is usually not included in ecological studies because it is difficult to evaluate. The use of non-invasive methods to determine pregnancy, without physically restraining individuals, would enable pregnancy to be included in population studies. In this study, we evaluated sex steroid hormones in plasma and fecal samples from pregnant and non-pregnant females to develop a pregnancy predictive model for guanacos (Lama guanicoe (Müller, 1776)). Samples were obtained during live-shearing management (i.e., capture, shear, and release) of guanacos. Enzyme immunoassays were used to evaluate progesterone (P4) and estradiol (E2) concentrations in plasma and pregnanediol glucuronides (PdG) and conjugated estrogens (EC) in feces. Mean hormonal and fecal metabolite concentrations were significantly higher in pregnant females than in non-pregnant females. A linear relationship was found between each hormone and its fecal metabolite. Finally, hormonal data were combined with an independent source of pregnancy diagnosis such as abdominal ballottement to develop a logistic regression model to diagnose pregnancy in non-handled individuals. The use of predictive models and non-invasive methods might be suitable to incorporate pregnancy information in large-scale population studies on guanaco and other free-ranging ungulates.

Effect of photoperiod on ovarian maturation in Cheirodon interruptus (Teleostei: Characidae).

Cheirodon interruptus is a ubiquitous small characid that inhabits the Pampean region and commonly used as bait. Its vast market is supplied from the wild population causing a significant environmental impact. In this study, we assess the effect of photoperiod on ovarian maturation in order to evaluate its potential as a tool to manipulate reproduction under artificial conditions. Four treatments in triplicate (light: dark, L: D) were tested: 24L: 0D, 12L: 12D, 0L: 24D and a progressive photoperiod corresponding to the daily photoperiod increments in wild during winter-spring transition, accelerated three times. The experiment was conducted for 45 days. Gonadosomatic index (GSI), oocyte mean diameter, vitellogenic oocyte proportions, plasma estradiol concentrations (E2), condition factor (Kn) and standard length were estimated. Values of mean GSI, oocyte diameter, vitellogenic oocyte proportions and E2 concentration were maximum in the progressive treatment indicating vitellogenesis stimulation. In turn the same parameters were minimum in the 24L: 0D, revealing the vitellogenesis inhibition. This study showed that photoperiodic regime play an important role in the onset of ovarian maturation in C. interruptus.

Transgender women on oral HIV pre-exposure prophylaxis have significantly lower tenofovir and emtricitabine concentrations when also taking oestrogen when compared to cisgender men.

IntroductionOral HIV Pre‐Exposure Prophylaxis (PrEP) with tenofovir (TFV) disoproxil fumarate (TDF)/emtricitabine (FTC) is highly effective. Transgender women (TGW) have increased HIV risk, but have been underrepresented in trials. For TGW on oestrogens for gender‐affirming hormone treatment (GAHT), TDF/FTC‐oestrogen interactions may negatively affect HIV prevention or gender‐affirming goals. Our aim was to evaluate any pharmacokinetic drug‐drug interaction between GAHT and TDF/FTC.MethodsWe performed a pharmacokinetic study, in an urban outpatient setting in 2016 to 2018, of the effects of GAHT on TFV, FTC and the active forms TFV diphosphate (TFV‐DP) and FTC triphosphate (FTC‐TP) in eight TGW and eight cisgender men (CGM). At screening, participants were HIV negative. TGW were to maintain their GAHT regimens and have plasma oestradiol concentrations >100 pg/mL. Under direct observation, participants took oral TDF/FTC daily for seven days. At the last dose, blood was collected pre‐dose, one, two, four, six, eight and twenty‐four hours, and colon biopsies were collected at 24 hours to measure drug concentration. TGW versus CGM concentration comparisons used non‐parametric tests. Blood and colon tissue were also obtained to assess kinase expression.ResultsPlasma TFV and FTC C24 (trough) concentrations in TGW were lower by 32% (p = 0.010) and 32% (p = 0.038) respectively, when compared to CGM. Plasma TFV and FTC 24‐hr area under the concentration‐time curve in TGW trended toward and was significantly lower by 27% (p = 0.065) and 24% (p = 0.028) respectively. Peak plasma TFV and FTC concentrations, as well as all other pharmacokinetic measures, were not statistically significant when comparing TGW to CGM. Oestradiol concentrations were not different comparing before and after TDF/FTC dosing. Plasma oestrogen concentration, renal function (estimated creatinine clearance and glomerular filtration rate), and TFV and FTC plasma concentrations (trough and area under the concentration‐time curve) were all correlated.ConclusionsGAHT modestly reduces both TFV and FTC plasma concentrations. In TGW taking GAHT, it is unknown if this reduction will impact the HIV protective efficacy of a daily PrEP regimen. However, the combination of an on demand (2 + 1 + 1) PrEP regimen and GAHT may result in concentrations too low for reliable prevention of HIV infection.

Effects of injecting increased doses of vitamins C and E on reproductive parameters of Holstein dairy cattle

Vitamins C and E have been supplemented separately to improve fertility in cattle. The objective of this study was to evaluate the effect of combined injections of increased doses of vitamins C and E on reproductive parameters in dairy cattle. Lactating Holstein cows (n= 44) were randomly assigned to one of three treatments: 1) Control: n= 15, cows were not injected with vitamins; 2) VCE3: n= 15, cows received a single intramuscular injection of 3,000 IU of vitamin E before estrus and multiple subcutaneous injections of vitamin C with a total dose of 3,000 mg before and after estrus; 3) VCE6: n= 14, cows were treated as in VCE3, but doses of vitamins C and E were increased to 6,000 mg and 6,000 IU. The reproductive indicators measured were diameter of the preovulatory follicle, time to estrus, area of the corpus luteum, pregnancy rate 35 and 45 d after AI and plasma concentrations of estradiol and progesterone. There was no effect of treatment on any of the evaluated reproductive parameters (P˃0.05), except that the lowest dose of vitamins sustained similar pregnancy rates among treatments, even though they had lower progesterone concentrations (P≤0.05) (19.4 ± 2.66 vs 10.1 ± 2.55 vs 19.2 ± 0.44 ng mL-1 for Control, VCE3 and VCE6, respectively). In conclusion, the supplementation with the highest amount of vitamin C and E (6,000 mg and 6,000 IU versus 3,000 mg and 3,000 IU) does not significantly increase the reproductive parameters measured.

Evaluation of molt induction using cassava meal varying the length of feeding period in older (90 week) laying hens.

Physiological changes during molt and postmolt egg production variables were compared among hens induced to molt by using cassava meal varying the length of the feeding period. Hens were randomly assigned to 3 treatments of 72 birds each: 1) molted by full feeding with cassava meal for 4 wk (CAS4); 2) molted by full feeding with cassava meal for 5 wk (CAS5); and 3) molted by full feeding with cassava meal for 6 wk (CAS6). All groups were fed a pullet developer diet for 2 wk following treatment. During the molt period, the birds were exposed to an 8L:16D photoperiod and had access to drinking water at all times. Thereafter, all hens were fed a layer diet (17.71% CP), and exposed to a 16L:8D photoperiod, and production performance was measured for 16 wk. The molt treatments resulted in total cessation of egg production in all treatments within 2 wk following feeding of the molt diet. BW loss of birds in the CAS6 treatment was approximately 41.81%, which was significantly higher (P < 0.05) than those in the CAS5 (37.63%) and CAS4 (31.89%) treatments. The CAS5 and CAS6 hens had significantly lower (P < 0.05) ovarian and oviducal weights than the CAS4 hens. No consistent differences were observed for concentrations of plasma estradiol and progesterone, bone quality, or mortality among the treatments. Postmolt feed consumption, egg weight, and mortality were not different (P > 0.05) as a result of molt induction method. However, the CAS4 hens had significantly higher (P < 0.05) cumulative egg production and lower feed conversion ratio than hens in the CAS6 treatment. Significant differences were found among treatments for Haugh units and shell thickness in some periods of the postmolt. It was concluded that cassava meal could be used to induce molt in laying hens effectively, feeding the molt diet for 4 wk produced optimum body weight loss and postmolt performance.