High Progesterone Concentrations Research Articles

Predictive Role of Progesterone Levels for IVF Outcome in Different Phases of Controlled Ovarian Stimulation for Patients With and Without Endometriosis: Expert View.

The study aimed to review the role of basal, trigger, and aspiration day progesterone levels (PLs) as predictors of in vitro fertilization (IVF) success for patients with and without endometriosis. A non-systematic review was conducted by searching papers published in English during the period of 1990-2023 in MEDLINE and PubMed, Embase, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), and Web of Science. The most widely used IVF predictor success was the trigger day progesterone serum level. Many studies utilize the threshold level of 1.5-2.0ng/ml. However, the predictive power of only progesterone level failed to show high sensitivity and specificity. Contrary, progesterone level on the trigger day combined with the number of mature retrieved oocytes had the highest predictive power. High baseline progesterone level was associated with poor IVF outcomes. Research on progesterone and IVF success in patients with endometriosis is limited but indicates that endometriosis patients seem to benefit from higher progesterone concentrations (≥ 37.1ng/ml) in IVF cycles. Currently, there is limited data for a definitive insight into the mportance of progesterone in the estimation of IVF success. Nonetheless, this summarized evidence could serve as up-to-date guidance for the role of progesterone in the prediction of IVF outcomes, both in patients with and without endometriosis.

Progesterone concentrations on blastocyst transfer day in modified natural cycle frozen embryo transfer cycles

Research questionAre serum progesterone concentrations on the day of modified natural cycle (mNC) frozen blastocyst transfer (FET) without luteal phase support (LPS) associated with clinical pregnancy rate (CPR)? DesignData were collected between January 2019 and October 2022 as a sub-study of an ongoing randomized controlled trial assessing pregnancy outcomes in mNC-FET. The sub-study included all women (n = 209) randomized to mNC-FET without LPS at the time of data extraction. Participants were aged 18–41 years, had regular menstrual cycles and underwent mNC-FET treatment with single-blastocyst transfer. Associations between the serum progesterone concentration on the day of blastocyst transfer and CPR, pregnancy rate and pregnancy loss rate (PLR) were examined between groups with low and higher progesterone concentrations using the 25th and 10th percentiles as cut-offs. Multivariate logistic regression analyses were performed to adjust for potential confounding factors. ResultsProgesterone concentrations on the day of blastocyst transfer in mNC-FET without LPS ranged from 4.9 to 91.8 nmol/l, with the 25th and 10th percentiles at 29.0 nmol/l and 22.5 nmol/l, respectively. Serum progesterone concentrations did not differ between women with or without a clinical pregnancy (mean [SD] 38.5 [14.0] versus 36.8 [12.4] nmol/l; P = 0.350). Furthermore, the CPR, pregancy rate and PLR were similar in women with low or high progesterone concentrations when using the 25th or the 10th progesterone percentile as cut-off. Multivariate regression analyses showed no association between progesterone concentrations and CPR. ConclusionsNo association was found between progesterone concentration on the day of blastocyst transfer and pregnancy outcome in women undergoing mNC-FET without progesterone LPS.

The intrafollicular concentrations of biologically active cortisol in women rise abruptly shortly before ovulation and follicular rupture.

What is the temporal activity and the concentration in follicular fluid (FF) of the anti-inflammatory steroid cortisol during the ovulatory process in humans? Intrafollicular concentrations of cortisol become massively upregulated close to ovulation concomitant with an exceptionally high biological activity securing a timely and efficient termination of inflammatory processes. Ovulation has been described as a local, controlled inflammatory process resulting in the degeneration of the follicle wall which facilitate oocyte extrusion. Ovulation also affects the glucocorticoid metabolism of granulosa cells (GCs) and although de novo synthesis of cortisol only occurs in the adrenal cortex, the mid-cycle surge has been shown to induce a change from high expression of HSD11B2, inactivating cortisol to cortisone, to high expression of HSD11B1 which reversibly catalyses cortisol production from cortisone. Furthermore, high concentrations of progesterone and 17OH-progesterone within follicles may cause dislodging of cortisol from cortisol binding protein (CBP) thereby activating the biological activity of cortisol. This prospective cohort study included 50 women undergoing fertility treatment according to a standard antagonist protocol at a university hospital-affiliated fertility clinic in Denmark. Women donated FF and GCs from one follicle for research purpose aspirated at one of four time points during the process of final maturation of follicles: T = 0 h, T = 12 h, T = 17 h, T = 32 h. A second sample was collected at oocyte pick up at T = 36 h. The concentration of cortisol and cortisone together with a range of sex steroids was measured by LC-MS/MS in FF collected at the five time points mentioned above. Whole genome microarray data, validated by q-PCR analysis, was used to evaluate gene expression of CYP11B1, CYP21A2, HSD11B1, HSD11B2, and NR3C1 in GCs at the same time points. The concentration of cortisol was significantly increased from a few nM at 0 h to around 100-140 nM (P ≤ 0.0001) at 32-36 h, whilst cortisone was almost constant from 0 to 17 h at a concentration of between 90 and 100 nM being significantly reduced to 25-40 nM (P ≤ 0.0001) at 32-36 h. This was paralleled by a 690-fold upregulation of HSD11B1 from 0 to 12 h increasing to a more than 20.000-fold change at 36 h. HSD11B2 was quickly downregulated 15- to 20-fold after ovulation induction. Concentrations of progesterone and 17OH-progesterone increased during the ovulatory process to high levels which in essence displaces cortisol from its binding protein CBP due to similar binding affinities. Furthermore, a significant decrease in 11-deoxycortisol expression was seen, but CYP11B1 expression was below detection limit in GCs. The study included women undergoing ovarian stimulation and results may differ from the natural cycle. More observations at each specific time point may have strengthened the conclusions. Furthermore, we have not been able to measure the actual active biological concentration of cortisol. For the first time, this study collectively evaluated the temporal pattern of cortisol and cortisone concentrations during human ovulation, rendering a physiological framework for understanding potential dysregulations in the inflammatory reaction of ovulation. This research was supported by the University Hospital of Copenhagen, Rigshospitalet, and Novo Nordisk Foundation grant number NNF21OC00700556. Interreg V ÔKS through ReproUnion (www.reprounion.eu); Region Zealand Research Foundation. The funders had no role in study design, collection of data, analyses, writing of the article, or the decision to submit it for publication. The authors have no conflicts of interest to declare. N/A.

Follicular dynamics in dairy sheep within and out of the breeding season employing high or low progesterone concentration in estrous cycle synchronization

Resumo A dinâmica folicular em ovelhas leiteiras é pouco compreendida. Neste trabalho foi avaliado a dinâmica folicular de ovelhas leiteiras, dentro e fora da estação reprodutiva observando o efeito de duas concentrações de progesterona (60 e 120mg) utilizadas em pessários vaginais na pré-sincronização. O experimento foi realizado nos meses de abril/maio e outubro/novembro, utilizando 40 ovelhas multíparas leiteiras hígidas, predominantemente da raça Lacaune, que foram submetidas a exames ultrassonográficos diários por via transretal. Na estação reprodutiva foram avaliados o número de ovulações (1,35 vs 1,05), o diâmetro(mm) do folículo ovulatório (5,97 vs 5,05), a duração da fase lútea (11 vs 9,14 dias) e a duração do ciclo estral (16,83 vs 16,6 dias) dentro da estação em comparação com fora da estação reprodutiva respectivamente. Fora da estação as ovelhas não apresentaram corpo lúteo no momento da inserção do pessário vaginal, caracterizando anestro. Mesmo com menor duração da fase folicular, o folículo ovulatório apresentou maior diâmetro na estação reprodutiva, sugerindo maior viabilidade e qualidade do oócito ovulado. A aplicação de progesterona exógena amplia a fase lútea na estação reprodutiva (11 vs 9,14 dias). O anestro observado fora de época sugere a necessidade de maior concentração de progesterona nos protocolos reprodutivos. Desta forma, é possível adaptar protocolos reprodutivos para diferentes épocas, sugerindo o uso de pessários vaginais com maior concentração de progesterona (120 mg) fora da estação reprodutiva. Os dados obtidos permitiram caracterizar a dinâmica folicular em ovelhas leiteiras, demonstrando suas diferenças em cada estação a partir do uso de diferentes doses de progesterona na pré-sincronização

Naturally menstruating women exhibit lower cardiovagal baroreflex sensitivity than oral contraceptive users during the lower hormone phase.

The present study evaluated cardiovagal baroreflex sensitivity (BRS) across the menstrual/pill cycle in naturally menstruating women (NAT women) and women using oral hormonal contraceptives (OCP women). In 21 NAT women (23±4 years old) and 22 OCP women (23±3 years old), cardiovagal BRS and circulating concentrations of estradiol and progesterone were evaluated during the lower hormone (early follicular/placebo pill) and higher hormone (late follicular to early luteal/active pill) phases. During the lower hormone phase, cardiovagal BRS up, down and mean gain were lower in NAT women (15.6±8.3, 15.2±6.1 and 15.1±7.1ms/mmHg) compared with OCP women (24.7±9.4, 22.9±8.0 and 23.0±8.0ms/mmHg) (P=0.003, P=0.002 and P=0.003, respectively), and higher oestrogen (R2 =0.15, P=0.024), but not progesterone (R2 =0.06, P=0.18), concentrations were predictive of lower BRS mean gain. During the higher hormone phase, higher progesterone concentrations were predictive of lower BRS mean gain (R2 =0.12, P=0.024). A multivariate regression model revealed group (NAT or OCP) to be a significant predictor of cardiovagal BRS mean gain in the lower hormone phase when hormone concentrations were adjusted for (R2 =0.36, P=0.0044). The multivariate regression model was not significant during the higher hormone phase (P>0.05). In summary, cardiovagal BRS is lower in NAT compared with OCP women during the lower hormone phase of the menstrual/pill cycle and might be associated with higher oestrogen concentrations. In contrast, during the higher hormone phase of the menstrual/OCP cycle, higher progesterone concentrations were predictive of lower cardiovagal BRS. NEW FINDINGS: What is the central question of this study? Does cardiovagal baroreflex sensitivity (BRS) differ between naturally menstruating women (NAT women) and women using oral contraceptives (OCP women)? What is the main finding and its importance? The main findings are as follows: (1) NAT women exhibit lower cardiovagal BRS than OCP women during the lower hormone phase of the menstrual or pill cycle; and (2) circulating oestrogen concentrations are significant predictors of cardiovagal BRS during the lower hormone phase, with higher oestrogen concentrations predicting lower BRS. The present data advance our understanding of the effect of endogenous ovarian hormones and OCP use on cardiovascular control mechanisms.

The concentration of kisspeptin, 17β-estradiol, progesterone and cortisol in the first trimester of pregnancy in cows

In clinically healthy Holstein cows (n=25), the dynamics of hormonal metabolism in the first trimester of cow pregnancy was studied. For this purpose, the concentration of kisspeptin, 17β-estradiol, progesterone and cortisol was determined in the blood serum of cows. The animals were regularly monitored with clinical and obstetricgynecological studies. The level of kisspeptin in the first trimester of pregnancy increased almost throughout the entire period under consideration with a decrease in concentration to 194.23±23.61 pg/ml on day 98. The level of estradiol during the first trimester increased from 49.66±9.68 to 76.20±17.84 pg/ml, respectively, which is also explained by the inclusion of the fetoplacental complex in its synthesis and secretion. Progesterone and cortisol levels were on average at the same level. During the experiment, out of 25 animals, embryonic death was recorded in 14 on the 30th day after insemination. As a result, two groups were formed: the 1st group - animals with a normal course of pregnancy and the 2nd group with embryonic death. Analyzing the data of enzyme immunoassay in animals of the 1st group, one can note a decrease in the level of kisspeptin by 11% on the 28th day compared to the 14th day after insemination. At the same time, the concentration of estradiol, on the contrary, increased by 29%. In the second group, on the contrary, the level of kisspeptin and estradiol did not change and, on average, remained almost at the same level. On the 28th day after insemination in the first group, the cortisol concentration was significantly higher compared to the second group - 15.32±3.23 and 9.00±0.89 nmol/l, respectively. Data for kisspeptin and estradiol showed no significant differences. However, it is of interest that in the first group, with an increase in the level of estradiol, a decrease in the level of kisspeptin occurs. In particular, this is consistent with previous studies, according to which such an interaction of these hormones can be regulated by a high concentration of progesterone.

Low progesterone concentration in early pregnancy is detrimental to conceptus development and pregnancy outcome in horses

High progesterone concentrations in the early luteal phase support pregnancy, whereas subphysiological progesterone concentrations delay embryonic development at least until placentation. In this study, fetal growth and development of pregnancy was investigated in pregnancies with prostaglandin F2α-induced low progesterone concentrations (PGF) in the early luteal phase and control pregnancies (CON) in the same mares (n = 12). Mares were inseminated and in PGF pregnancies received the prostaglandin F2α analogue cloprostenol (62.5 µg) on days 0–3 after ovulation to induce subphysiological progesterone concentrations; CON pregnancies remained untreated. Mares were assigned to PGF or CON treatments in alternating order and received the opposite treatment in the following year. Blood was collected and conceptus size determined repeatedly by transrectal (≤day 101) and transabdominal (>day 101) ultrasonography. After birth, foals were weighed, measured and submitted to a clinical examination. Treatment PGF resulted in fewer pregnancies than CON treatment. All foals born from CON pregnancies were healthy and mature, whereas 4/7 PGF pregnancies were either lost (one embryonic death, one abortion) or resulted in the birth of compromised foals (P = 0.018). Size of the conceptus (e.g., diameter day 49: PGF 6.6 ± 0.7, CON 7.7 ± 0.7 cm, P = 0.006) and embryo proper (e.g., crown rump length day 54; PGF 4.4 ± 0.8, CON 5.8 ± 0.6 cm, P = 0.015) differed between treatments. These size differences decreased over time and at birth PGF foals did not differ significantly from CON foals. In conclusion, reduced progesterone concentration in the early luteal phase leads to delayed conceptus growth beyond placentation and increased pregnancy loss.

O-247 The intrafollicular inflammatory response during ovulation in women is most likely controlled by high concentrations of active cortisol being synthesized shortly before follicular rupture

Abstract Study question How is the anti-inflammatory response in human follicles controlled during the ovulatory process leading to the expulsion of the oocyte? Summary answer Intrafollicular concentrations of cortisol becomes high close to ovulation concomitant with an exceptionally high biological activity securing a timely and efficient termination of inflammatory processes. What is known already Ovulation has been described as a local controlled inflammatory process resulting in the degeneration of the follicle wall to facilitate oocyte extrusion. Ovulation also affects glucocorticoid metabolism of granulosa cells (GC) and although de novo synthesis of cortisol only occurs in the adrenal cortex the mid-cycle surge induces a change from high expression of HSD11b2, inactivating cortisol to cortisone, to high expression of HSD11b1 which reversibly catalyses cortisol production from cortisone. Furthermore, the high concentrations of progesterone and 17-OH-progesterone within follicles cause dislodging of cortisol from cortisol binding protein (CBP) thereby activating the biological activity of cortisol. Study design, size, duration This prospective study included 50 women undergoing fertility treatment according to a standard antagonist protocol at the fertility clinic at the university hospital of Koege, Denmark. Women donated one follicle for research purpose aspirated at one of four time points during the process of final maturation of follicles; T = 0h, T = 12h; T = 17h; T = 32h and then one additional follicle at OPU at T = 36h Participants/materials, setting, methods The concentration of cortisol and cortisone together with sex steroids were measured by LC-MS/MS in follicular fluid (FF) collected at the above five time points. Whole genome microarray data, validated by q-PCT analysis, was used to evaluate gene expression of CYP11b1, CYP21A2, HSD11b1, HSD11b2 and NR3C1 in GC at the five different time points. Main results and the role of chance The expression of HSD11b1 is strongly upregulated during the ovulatory process. From 0-12h expression is increased 690 times reaching more than 20.000 times higher than at T = 0 during the remaining period. In contrast, expression of HSD11b2 is quickly downregulated by 15-20 times through the ovulatory process. The concentration of cortisol is different from the gene expression but increases significantly from a few ng/ml at T = 0h to around 15 ng/ml at T = 12h—17h and peaks at 40-50 ng/ml at T = 32h—36h. In contrast, cortisone is almost constant from 0 to 17h at a concentration of 30-40 ng/ml being significantly reduced to 10-20 ng/ml at T = 32—36h. Concentrations of progesterone and 17-OH-progesterone increased during the ovulatory process to high levels which in essence displaces cortisol from its binding protein CPB, due to similar binding affinities. This will contribute to high levels of biologically active cortisol close to ovulation, which allows the inflammatory reaction to act on the follicle wall and secure extrusion of the oocyte to oviduct before becoming inhibited by cortisol. Furthermore, a significant decrease in 11-deoxycortisol expression was seen but CYP11B1 expression was below detection limit in GCs. This study provides new information on human ovulation. Limitations, reasons for caution Although 50 women were included more observations at each specific time point would have strengthened the conclusions. Wider implications of the findings For the first time, this study collectively evaluates the temporal effect of cortisol and cortisone concentrations in connection with gene expression profiles of enzymes involved in regulation the inflammatory response during human ovulation which now forms a physiological framework for understanding potential dysregulations in the involved processes. Trial registration number NA

Impact of progesterone concentration on human chorionic gonadotropin trigger day on clinical outcomes with one top-quality cleavage-stage embryo or blastocyst transfer in fresh in vitro fertilization cycles.

To investigate the impact of the progesterone concentration on the human chorionic gonadotropin (hCG) trigger day on clinical outcomes with an antagonist protocol. The retrospective cohort study included a total of 1,550 fresh autologous ART cycles with one top-quality embryo transfer. Multivariate regression analysis, curve fitting, and threshold effect analysis were performed. A significant association was found between the progesterone concentration and clinical pregnancy rate (adjusted OR, 0.77; 95% CI, 0.62-0.97; P = 0.0234), especially in blastocyst transfer (adjusted OR, 0.56; 95% CI, 0.39-0.78; P = 0.0008). The association between the progesterone concentration and the ongoing pregnancy rate was insignificant. The clinical pregnancy rate showed a linear relationship with an increased progesterone concentration in cleavage-stage embryo transfer. In blastocyst transfer, as the progesterone concentration increased, the clinical and ongoing pregnancy rates showed a parabolic reverse-U curve; the curve initially increased before declining at high progesterone concentrations. The clinical pregnancy rate increased with a progesterone concentration up to 0.80 ng/mL rather than tended to be stable. The clinical pregnancy rate significantly decreased when the progesterone concentration was ≥0.80 ng/mL. The progesterone concentration on the hCG trigger day exhibits a curvilinear relationship with pregnancy outcomes in blastocyst transfer cycles, and the optimal threshold of the progesterone concentration is 0.80 ng/mL.

Effects of sub-physiological plasma progesterone concentration in the early luteal phase on embryonic and fetal development, pregnancy outcome and foal characteristics

High progesterone concentration in the early luteal phase supports pregnancy and postovulatory progestin treatment stimulates conceptus growth (Willmann et al., Theriogenology 2011;75,421) whereas reduced progesterone concentration changes histotroph composition (Beyer et al., Theriogenology 2019;125:236). Embryos obtained on day 34 from mares with reduced progesterone concentration were less developed than embryos from control pregnancies (Okada et al., Reprod Fert Develop 2020;32:1156). Sub-physiological progesterone concentrations in early pregnancy thus delay embryonic development at least until placentation. In this study, subsequent fetal growth, pregnancy loss and foal characteristics were investigated in pregnancies with reduced progesterone concentrations in the early luteal phase (PGF; n=7) and control pregnancies (CON; n=7) in the same mares. Estrous mares were inseminated every 48h until ovulation (day 0). Group PGF received 62.5µg of the prostaglandin F2α analogue cloprostenol daily on days 0-3 to induce sub-physiological progesterone concentrations whereas CON pregnancies remained untreated. Mares were assigned to PGF and CON treatments in alternating order and received the opposite treatment in the following year. Blood was obtained and conceptus size determined by transrectal (≤day 100) and transabdominal (>day 100) ultrasonography at regular intervals. IgG concentration was determined in colostrum at foaling and in foal plasma at 18-22 hrs after birth. Foals were weighed,measured, submitted to a clinical examination and the neutrophil / lymphocyte (N / L) ratio was determined as an indicator of maturity. Time from birth to first standing and first suckling was recorded. Data were analyzed with the SPSS statistics software, using two-way repeated measures ANOVA and χ2 analysis. Progesterone concentration was reduced in the first two weeks of PGF pregnancies (p<0.001; day 7 CON 35±3, PGF 11±2 ng/ml). All foals from CON pregnancies were healthy and mature, whereas 3/7 PGF pregnancies were lost (one embryonic death, one abortion, one non-viable foal, p=0.05). Size of the conceptus (day 49: PGF 6.6±07, CON 7.7±07 cm, p=0.006), embryo proper (day 54; PGF 4.4±0.8, CON 5.8±0.6 cm, p=0.015) and fetal orbita diameter (day 73 PGF 0.7±0.1, CON 1.0±0.1 cm, p=0.007) were smaller in PGF than in CON pregnancies. Size differences between PGF and CON pregnancies decreased over time and were no longer present at foaling. The viable PGF foals also did not differ in N / L ratio and time to standing and first suckling from CON foals In conclusion, reduced plasma progesterone concentration in the early luteal phase delays fetal growth beyond placentation and increases pregnancy loss. When viable foals are born, however, they are not compromised. Results indicate that pregnancies with sub-physiological progesterone concentrations will benefit from early progestogen substitution.

Atretic preovulatory follicles could be precursors of ovarian lutein cysts in the pig

Ovarian cysts contribute to reduced reproductive performance in pigs. Unfortunately, the mechanism of lutein cysts formation remains unknown. Here, we compared the endocrine and molecular milieus of intact, healthy preovulatory follicles (PF), gonadotropin (eCG/hCG)-induced healthy and atretic-like PF, as well as gonadotropin-provoked and spontaneous ovarian cysts in gilts. Several endocrine and molecular indicators and microRNA were compared in walls of PF and cysts. Intact and healthy PF, showed high estradiol/androstendione and low progesterone levels associated with CYP17A1, HSD17B1, and CYP19A1 elevation and reduced StAR/HSD3B1 protein expression. In contrast, low estradiol/androstendione and high progesterone concentrations, accompanied by decreased CYP17A1, HSD17B1, CYP19A1 and increased HSD3B1 protein abundance, appeared in atretic-like PF, gonadotropin-induced and spontaneous cysts. High progesterone receptor (PGR) protein abundance was maintained in intact and healthy PF, while it dropped in atretic-like PF, gonadotropins-induced and spontaneous cysts. The atretic PF showed high level of TNFα compared to healthy PF. In conclusion, follicular lutein cysts could be recruited from atretic-like PF with lost estrogenic milieu and inability to ovulate. Ovulatory cascade was presumably disrupted by a low PGR and high TNFα levels associated with earlier luteinization of follicular walls. These results suggest a novel mechanism of lutein ovarian cysts development in pigs and, perhaps, other species.

152 The effect of high or low concentration of progesterone during diestrus and its association with intensity of oestrus in lactating Holstein cattle

152 The effect of high or low concentration of progesterone during diestrus and its association with intensity of oestrus in lactating Holstein cattle

153 The effect of high or low concentration of progesterone during diestrus and its association with the LH surge and PGF2α metabolite in lactating Holstein cattle

153 The effect of high or low concentration of progesterone during diestrus and its association with the LH surge and PGF2α metabolite in lactating Holstein cattle

Transfer of bovine embryos into a uterus primed with high progesterone concentrations positively impacts fetal development at 42 days of gestation

Elevated circulating progesterone (P4) concentrations in the first week after conception have been associated with accelerated post-hatching conceptus elongation. However, the consequences, if any, on the development of the fetus are unknown. The objective of this study was to determine the relationship between early circulating P4 and fetal and placental morphometric characteristics at 42 days of gestation. A previously validated model of asynchronous embryo transfer (ET), known to alter uterine exposure to P4, was used in 107 heifers divided in two replicates (replicate 1: n = 51, replicate 2: n = 56). Heifers were randomly assigned to one of the two following groups: those receiving a Day 7 embryo on Day 7 of the cycle (synchronous; ET_D7, n = 49) and those transferred a Day 7 embryo on Day 9 of the cycle (asynchronous; ET_D9, n = 58). The synchronization protocol was started two days earlier for heifers in the ET_D9 group such that ET was done on the same day for both groups. P4 concentrations were determined from Day 3 after estrus to the day of ET. Pregnant heifers were slaughtered at Day 42 of gestation for fetal and placental morphometric measurements. The effects of the group, replicate, fetal sex, and interactions between these variables on fetal and placental characteristics were determined by ANOVA, while Pearson correlation was employed to assess the linear relationship between P4 concentrations two days before and on the day of ET on the fetal parameters. The uteri of heifers in the ET_D9 group were exposed to higher concentrations (P < 0.0001) of P4 from four days before ET, than heifers in the ET_D7 group. Both group and fetal sex variables impacted on fetal crown-rump length (CRL) (group: P < 0.0001, sex: P = 0.001) and fetal weight (group: P = 0.006, sex: P = 0.003). Fetal sex influenced the amniotic sac area (P = 0.003) and amniotic sac weight (P = 0.004); while the group affected the number of cotyledons (P = 0.0009), and the fetal heart weight (P = 0.018). All these parameters were larger in the ET_D9 group compared with ET_D7, and in males compared with females. There was a positive correlation between P4 concentrations two days before ET and fetal weight and CRL, for each sex or considering all fetuses (R2 ∼0.4, p < 0.05). In conclusion, bovine embryos transferred into a uterus primed with higher P4 concentrations underwent enhanced development reflected in higher weight and size at the beginning of the fetal period.

Tracking reproductive events: Hoof growth and steroid hormone concentrations in hair and hoof tissues in moose (Alces alces).

Measurements of reproductive and stress-related hormones in keratinous tissues (e.g. hair, claws, hooves, baleen) can provide a record of stress and reproductive response in wildlife. We evaluated a method to collect keratin tissue from hooves of immobilized moose (Alces alces) and validated enzyme immunoassays for measuring cortisol and progesterone in hooves and hair. We also measured the annual growth and wear rates of moose hooves. Progesterone (range: 1.0-43.7pg/mg) and cortisol (range: 0.05-2.9pg/mg) were measurable and showed variation among hoof samples and moose. Pregnant females had twice as high progesterone concentrations (18.00 ± 3.73pg/mg) from hoof sample locations post breeding compared to non-pregnant moose (9.40 ± 0.25pg/mg). Annual hoof growth differed between the front (5.58 ± 0.12cm) and rear (4.73 ± 0.13cm) hooves and varied by season with higher growth rates during summer which decreased into autumn and winter. Adult female hooves represented between 1.6 and 2.1years of growth and included up to two reproductive cycles. We established a method to estimate hoof growth rate and applied this to postmortem samples and were able to detect previous pregnancies. Shoulder guard hairs grew between August and March including during late gestation; however, hair progesterone concentrations (range: 2-107.1pg/mg) were not related to reproductive state. Hair cortisol concentrations in our study (range: 0.2-15.9pg/mg) were within the range of values previously reported for cervids. Our study supports the use of hooves for longitudinal sampling and measuring reproductive and stress-related hormones, providing a new tool for tracking reproductive events and understanding what variables may contribute to population level changes in reproduction.

Progesterone Promotes In Vitro Maturation of Domestic Dog Oocytes Leading to Successful Live Births.

Gene-edited dogs are promising models for biomedical research because they have hundreds of genetic diseases that are similar to humans. A common method for producing gene-edited dogs is assisted reproductive technology (ART) using in vivo oocytes or embryos, but it is much more inefficient and has a higher cost. ART for dogs has lagged mostly because of the lack of an efficient in vitro maturation system. Because early maturation of canine oocytes occurs in follicles with extremely high concentrations of progesterone (P4), we hypothesize that P4 has an important role during maturation. In this study, we obtained ovaries of female dogs and collected cumulus-oocyte complexes, which were cultured in vitro in microdrops containing different P4 concentrations (0, 10, 40, 100 or 200 µg/mL). We found that 40 µg/mL P4 produced the highest oocyte maturation rate (29.7% ± 7.1%, p &lt; 0.05). We also evaluated the quality of in vitro matured oocytes by in vitro fertilization and single-cell RNA sequencing, and both indicated an improvement in oocyte developmental potential. In conclusion, we successfully obtained the first live dogs using in vitro matured oocytes by adding P4 to optimize the in vitro maturation system of canine oocytes, and established a new and low-cost method to produce dogs via in vitro maturation and in vitro fertilization.

Pregnancy rate and reproductive hormones in humpback whale blubber: Dominant form of progesterone differs during pregnancy

To better understand reproductive physiology of humpback whales Megaptera novaeangliae that reside in Hawai’i and Alaska, enzyme immunoassays were validated for both progesterone and testosterone in free-ranging and stranded animals (n = 185 biopsies). Concentrations were analyzed between different depths of large segments of blubber taken from skin to muscle layers of stranded female (n = 2, 1 pregnant, 1 non-pregnant) and male (n = 1) whales. Additionally, progesterone metabolites were identified between pregnant (n = 1) and non-pregnant (n = 3) females using high pressure liquid chromatography (HPLC). Progesterone concentrations were compared between juvenile (i.e., sexually immature), lactating, and pregnant females, and male whales, and pregnancy rates of sexually mature females were calculated. Based on replicate samples from ship struck animals collected at 7 depth locations, blubber containing the highest concentration of progesterone was located 1 cm below the skin for females, and the highest concentration of testosterone was in the skin layer of one male whale. HPLC of blubber samples of pregnant and non-pregnant females contain different immunoreactive progesterone metabolites, with the non-pregnant female eluate comprised of a more polar, and possibly conjugated, form of progesterone than the pregnant female. In females, concentrations of progesterone were highest in the blubber of pregnant (n = 28, 28.6 ± 6.9 ng/g), followed by lactating (n = 16, 0.9 ± 0.1 ng/g), and female juvenile (n = 5, 1.0 ± 0.2 ng/g) whales. Progesterone concentrations in male (n = 24, 0.6 ng/g ± 0.1 ng/g) tissues were the lowest all groups, and not different from lactating or juvenile females. Estimated summer season pregnancy rate among sexually mature females from the Hawai’i stock of humpback whales was 0.562 (95 % confidence interval 0.528–0.605). For lactating females, the year-round pregnancy rate was 0.243 (0.09–0.59), and varies depending on the threshold of progesterone assumed for pregnancy in the range between 3.1 and 28.5 ng/g. Our results demonstrate the synergistic value added when combining immunoreactive assays, HPLC, and long-term sighting histories to further knowledge of humpback whale reproductive physiology.

Study of progesterone level during first trimester of pregnancy in cows.

Measurement of progesterone is an indirect method for pregnancy diagnosis in many livestock species including cattle, buffaloes, sheep, and goats. Conception extends the life of the corpus luteum (CL) by preventing the luteolytic mechanism from being triggered, thus prolonging and maintaining its functional characteristics, ensuring continued high progesterone levels (Spencer, et.al., 1995). (Shemesh et al., 1973) proposed that the difference in peripheral plasma progesterone levels between pregnant and non pregnant cows, 19 days after insemination, can form the basis for a very early pregnancy test. (Laing and Heap 1972) first documented this in milk to diagnose cows in early pregnancy Progesterone maintains the uterine endometrium in a state which supports embryonic development, implantation, and foetoplacental development. Progesterone concentrations vary with the stage of the estrous cycle which makes it one of the most commonly studied reproductive hormones in bovine ruminants for pregnancy detection and ovarian activity (Kaneko,et.al.,1994). Studies in the bovine estrous cycle indicate that the milk or serum progesterone concentrations reach a maximum value 13-14 days after estrus, and if the animal is pregnant, these continue to remain elevated up to day 21 after fertilization (Parkinson, et al.,1994) . These high levels of progesterone in serum or milk between days 18 and 24 after insemination form the basis of establishment of pregnancy in cattle (Sasser, and Ruder,1987; Shemesh,1973). Interferon-???? exerts its antiluteolytic effect by inhibiting the endometrial expression of oxytocin receptors, through which oxytocin stimulates pulsatile PGF2???? release (Wolf,2003). Although low progesterone concentrations at 18 to 24 days after breeding can accurately predict non pregnancy, high progesterone concentrations during this period are not the specific indicators of pregnancy due to variations among cows in duration of the estrous cycle as well as the incidence of early or late embryonic mortality. The advantages of progesterone assay for pregnancy diagnosis include noninvasive collection of milk sample and the feasibility to conduct the test on the farm using commercial cow-side milk progesterone test kits [Pennington,1985 ; Gowan,1982 ; Wimpy,et.al.,1986), though the sensitivity gets compromised to some extent with these assay kits.&#x0D; Key Word: progesterone, pregnancy, cows

Drp1 Expression and Phosphorylation in Steroidogenic Corpus Luteum during the Estrous Cycle in Rat Ovaries.

In response to luteinizing hormone (LH), a higher concentration of progesterone (P4) is produced in luteal cells of corpus luteum (CL). Mitochondria are an essential cellular organelle in steroidogenesis. The specific engagement of the concept regarding mitochondrial shaping with early stages of steroidogenesis was suggested in reproductive endocrine cells. Although the specific involvement of GTPase dynamin-related protein 1 (Drp1) with steroidogenesis has been demonstrated in luteal cells of bovine CL in vitro, its actual relationship with ovarian steroidogenesis during the estrous cycle remains unknown. In this study, while Fis1 and Opa1 protein levels did not show significant changes during the estrous cycle, Drp1, Mfn1, and Mfn2 proteins exhibited relatively lower levels at proestrus than at estrus or diestrus. 3β-HSD showed higher levels at proestrus than at estrus or diestrus. In addition, Drp1 phosphorylation (s637) was higher in proestrus than in estrus or diestrus. Immune-positive cells for Drp1, pDrp1 (s637), and 3β-HSD were all localized in the cytoplasm of luteal cells in the CL. The immune-positive cells for 3β-HSD were more frequently seen in the CL at proestrus than at estrus or diestrus. Immunoreactivity for Drp1 in luteal cells at proestrus was weaker than that at estrus or diestrus. However, pDrp1 (s637) immune-positive cells were mostly detected in luteal cells at proestrus. These results imply that steroidogenesis (P4 production) in the CL is closely related to phosphorylation of Drp1 at serine 637. Taken together, this study presents evidence that Drp1 phosphorylation at serine 637 is an important step in steroidogenesis in the CL.

Seasonal Pattern in Serum Estradiol, Progesterone, and Prolactin Concentrations in Rescued Wild Female Taiwanese Pangolin (Manis pentadactyla pentadactyla)

Pangolins are under severe threat of surging poaching rates globally; therefore, there is a demand to ascertain reproductive measures to ensure captive breeding and management strategies. Due to the absence of substantial information on the pangolin, endocrinology and reproductive physiology studies around the globe are merely based on captive observations that have failed to report the chronographs and hormonal cyclicity of the reproductive events. This study attempts to evaluate the annual pattern of reproductive steroids (estradiol-17β and progesterone) and prolactin in 16 wild female Taiwanese pangolins rehabilitated by Pingtung Rescue Center of Endangered Wild Animals, Taiwan. Novel immunoassays, i.e., chemiluminometric assays, have been used to quantify the serum reproductive steroids and contribute to a better understanding of the endocrine correlates of function in the Taiwanese pangolin. The hematological findings were characterized by monthly median concentration. The circulating reproductive hormones demonstrated seasonal reproductive activity by confirming a peak in serum estradiol concentrations in December and considerably higher progesterone concentrations in November/December, and March/April. The rise in prolactin in December and peak values in April suggest participation in the ovulatory process and mating. Collectively, these findings can help maximize the reproductive efficiency of pangolin species in captivity, i.e., by timely pairing and prioritizing the care of the breeding pairs to optimize breeding efforts and, therefore, effectively support conservation breeding programs and restore the natural population in the ecosystems.