Made available in DSpace on 2014-06-11T19:29:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-07-23Bitstream added on 2014-06-13T18:58:56Z : No. of bitstreams: 1 dias_cc_me_botfmvz.pdf: 323339 bytes, checksum: 725d51a35fb86fca8619ebfdadfe86cd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste experimento foi avaliar a influência da concentração sérica de progesterona ([P4]) nos dias (d) 0 e/ou d7 do protocolo de sincronização da ovulação e da reutilização de dispositivo intravaginal de progesterona (CIDR) nos resultados a IATF em novilhas Nelore ciclando (n=398). O protocolo utilizado foi: d0-CIDR [sem utilização prévia (1ºuso), previamente utilizados por 9d (2ºuso) ou 18d (3ºuso)]+BE(2mg)+amostra de sangue para dosagem [P4], d7-PGF2(12,5mg)+amostra de sangue para dosagem [P4], d9-retirada do CIDR®+ECP(1mg), d11-IATF+mensuração do Fol, d13-avaliação da ovulação e d41-diagnóstico de gestação. Variáveis contínuas foram analizadas pelo PROC-GLM e binomiais pelo PROC-LOGISTIC do SAS. Foi considerada diferença estatística P<0,05 e tendência P<0,1. A [P4d0] influenciou de forma positiva Fol, concepção e prenhez. A [P4d7] não influenciou os parâmetros avaliados. O Fol, foi menor para 1uso (10,10,19mm) do que 3uso (11,00,21mm) e 2uso (10,60,20mm) não diferiu dos demais. A taxa de sincronização das classes de Fol diferiram entre si (Classe1:Fol<8,5, 28,2%, Classe2:8,5-10,0, 62,5%, Classe3:>10mm, 92,2%. A taxa de concepção das classes de Fol foi avaliada de acordo com o número de utilizações do CIDR no 1º e 2º usos as classes 1 e 2 tiveram menor concepção do que a Classe3, mas no 3ºuso as classes tiveram concepção similar (Classe1, 9,1%, 0%, 40,0%, Classe2: 24,0%, 21,7%, 54,5% Classe3, 52,4%, 48,9%, 53,8%, 1, 2 e 3usos respectivamente). A taxa de concepção, tendeu a ser maior com 3uso (53,2%) que 1ºuso (37,2%) e 2uso (37,8%). A taxa de prenhez, foi maior com 3ºuso (35,5%) que 1uso (20,5%) e 2uso (22,7%). / The aim of this study was to evaluate if progesterone concentrations [P4] on d0 and/or d7 of a protocol and if reutilization of intravaginal progesterone devices (CIDR) could affect FTAI success in Nellore cycling heifers. Heifers (n=398) received the protocol: d0: CIDR (with no previous use (1stuse), previously used for 9d (2nduse) or previously used for 18d (3rduse)) + EB(2mg) + blood samples to determine [P4d0], d7: PGF2 + blood sample to determine [P4d0], d9: CIDR® withdraw + ECP(1mg), D11: FTAI + largest follicle diameter measurement (Fol), D13: check ovulation and D41: pregnancy diagnoses. Continuous variables were analyzed by PROC-GLM and binomial by PROC-LOGISTIC of SAS. Statistical difference was considered with P<0,05 e tendency P<0,1. The [P4d0] positively influenced Fol, conception and pregnancy rates. The CIDR number of uses influenced [P4d7] (1stuse 2.4±1.1; 2nduse 2.0±1.0 and 3rduse 1.7±1.1ng/ml), but [P4d7] didn’t influence studied parameters. The Fol, was smaller on 1stuse (10,10,19mm) compared to 3rduse (11,00,21mm) and 2nduse (10,60,20mm) didn’t differ from others. Synchronization of Fol classes differed (Class1:Fol<8.5, 28,2%, Class2:8.5-10.0, 62.5%, Class3:>10mm, 92,2%. Conception of Fol classes were evaluated by CIDR number of uses. On 1st and 2nduse classes1 and 2 had lower conception compared to class3, but on 3rduse classes conceptions were similar (Class1, 9.1%, 0%, 40.0%, Class2: 24.0%, 21.7%, 54.5% Class3, 52.4%, 48.9%, 53.8%, 1st, 2nd and 3rduse, respectively). Conception tended to be higher on 3rduse (53.2%) compared to 1stuse (37.2%) and 2nduse (37.8%). Overall pregnancy was higher on 3rduse (35.5%) compared to 1stuse (20.5%) and 2nduse (22.7%).

Non-genetic maternal influences on prenatal development have a significant effect on the development of early life behavior. This study assessed the behavioral effect of elevated prenatal progesterone on postnatal emotional reactivity, or underlying fear and stress, in embryos of Northern bobwhite quail (Colinus virginianus). Test groups of progesterone treated eggs, vehicle treated, and no injection were exposed to three measures of emotional reactivity at 48 and 96 hours after hatch: an open field, an emergence test, and a tonic immobility test. Heightened levels of emotional reactivity in the tonic immobility emergence tasks, and decreased levels of emotional reactivity in the open field suggest that elevated prenatal progesterone modifies post natal emotional reactivity up to 96 hours of age.

17β-Estradiol (E2) and progesterone (P4) have various important functions but the effect of these endogenous hormone concentrations on fibrin network formation has not been established. It is essential to understand natural hormone mechanisms since these hormones are still present in circulation while hormonal contraceptives, which are associated with increased risk of venous thromboembolism, are used. In this study the formation of a fibrin network is analysed when different physiological concentrations of E2 and P4 is added to platelet poor plasma. Blood coagulation is critical for haemostasis but when the formation of a stable clot is influenced in such a way that hypercoagulation takes its course, it can have detrimental effects as it increases the risk of venous thrombosis. During blood coagulation fibrinogen is converted into fibrin in the presence of thrombin. The formation of a dense fibrin clot structure is quite an intense process and packaged in very specific ways. Both E2 and P4 has the ability to shift the haemostatic balance to a hypercoagulable state and therefore viscoelastic studies, morphological analysis as well as turbidimetry were used in this study to observe the possible changes in the fibrin network formation. Viscoelastic studies included thromboelastography (TEG) which gave insight to the properties of clot formation. Morphological studies included scanning electron microscopy (SEM) and atomic force microscopy (AFM) which delivered an investigation in fibrin network morphology, fibrin fiber diameter and surface roughness. Turbidimetry included further analysis of plasma fibrin clot formation and clot lysis time (CLT). Results showed that E2 and P4 showed hypercoagulable viscoelastic properties with decreased fibrin diameter and surface roughness while increased occurrence of dense matted deposits (DMDs) were evident. Turbidimetry showed decreased CLT for E2, but not P4. These results suggest in the presence of endogenous estrogen and progesterone, which is associated with hypercoagulability, the additional burden of synthetic hormones may result in a prothrombotic and hypercoagulable state in females with an inflammatory predisposition. It appears that both E2 and P4, which are known for their anti- and pro-inflammatory action, may influence fibrin network formation on a molecular level. These results are of clinical importance when considering hormones as either a pathological agent or therapeutic intervention. / Dissertation (MSc)--University of Pretoria, 2016. / Physiology / MSc / Unrestricted

Hormones play a crucial role in promoting and maintaining many important processes. Progesterone, in particular, is involved in reproductive health, pregnancy maintenance, and hormone-dependent cancers. Many hormonal-based therapeutics are delivered systemically, resulting in side effects for the user or the development of resistance to the delivered agent. This project sought to develop a progesterone-specific nanoparticle-based system for localized modulation of progesterone. The aims included development of the particle, with the use of anti-progesterone antibodies, development of a measurement system to determine relevant, physiological levels of progesterone to validate the proof-of-concept studies, and testing of the particle against the developed progesterone measurement system. The development of the particle progressed in stages, beginning with the generation of oleic acid-coated superparamagnetic iron oxide nanoparticles (SPIONs). Much of the particle development efforts focused on the initial thermal decomposition reaction utilized to develop these SPIONs. Optimization focused on improvement of synthesis parameters to improve yield and reduce particle polydispersity, with reaction modifications resulting in improvement of yield more than threefold, a reduction in particle polydispersity, and an increase in the uniformity of particle morphology. The next phase of particle design was the generation of citric acid-coated SPIONs, followed by addition of polyethylene glycol with active sites for the conjugation of anti-progesterone antibodies. Finally, antibodies were successfully conjugated to the surface of the particles, validated with protein absorbance at 280 nm. Additionally, several standard curves for progesterone, ranging in concentration from 0 to 50 g/mL, with values of the coefficient of determination for the linear curves greater than 0.9 for all the tested methods, were generated. Specifically, standard curves were generated in ethanol, as well as ethanol diluted in both water and phosphate buffered saline to better replicate physiological conditions. All three solutions resulted in linear standard curves for confident determination of the concentration of solutions of progesterone. Finally, the ability of the particles to bind to progesterone was successfully validated using UV absorbance at 241 nm by comparing the progesterone remaining after wash steps for antibody-particles, blank-particles, and the progesterone standard solution. This project resulted in the successful development of anti-progesterone antibody conjugated nanoparticles, validation of the specificity of the particles for progesterone, linear standard curves for progesterone in a variety of solutions, and optimization of the oleic acid SPION synthesis reaction. Future efforts should focus on the detection of progesterone at concentrations below 200 ng/mL, as this was a primary challenge in both the development of the progesterone concentration assay and the testing of the affinity of the particles for progesterone. Future research should focus on the optimization of the antibody-conjugation process to maximize coating density while minimizing loss of unconjugated antibody and further development of the testing conditions to determine the duration of treatment and the strength of the affinity of the particles for progesterone. / 2025-05-24T00:00:00Z

Fertility is the most important factor controlling mammalian reproduction. Bull fertility, ability of the sperm to fertilize and activate the egg, and support embryonic development is crucial for early development. Similarly, the hormonal environment of the embryo also plays a critical role in successful embryonic development. We know that molecular health of the sperm as well as progesterone enhancing the development of the embryo is important for early development and implantation. The gaps in the knowledge base are 1) how early mammalian embryo development is paternally affected is not fully clear and 2) how progesterone improves the survival of the transferred embryo in the uterus still remains elusive. The central hypothesis was that low expression of MHC1 and Magel2 would cause a dysfunction in early embryo development and that progesterone will increase the survivability of the embryo via its associations with TNF-alpha and PGF2alpha. The objectives of this study were to 1) determine the expression of mhc1 and magel2 in single in vivo and in vitro blastocysts derived from low fertility and high fertility sires as well as to determine main pathways by which protein products of these genes regulate early development, and 2) identify the role of progesterone in regulating TNF-alpha and PGF2alpha. To accomplish these goals, we performed real time reverse transcriptase reaction and bioinformatics approaches, and ELISA and commercially available radioimmunoassay kits, respectively. The results of the experiments showed that 1) expression of mhcI transcripts were greater in high fertility in vivo embryos compared to their low fertility in vivo counterparts. Magel2 results showed an increase (P ≤ 0.05) in expression levels of high fertility in vivo embryos compared to their high fertility in vitro counterparts. Low fertility in vivo embryos had higher expression than high fertility in vitro embryos as well.

Progesterone is essential for the maintenance of pregnancy in cattle. Recent trends in decreased reproductive efficiency in dairy cattle have led researchers to believe that increased catabolism and decreased peripheral concentrations of progesterone are at fault. The objective of this study was to determine if the induction of an accessory corpus luteum (CL), via human chorionic gonadotropin (hCG), alters blood perfusion of CL, peripheral concentrations of progesterone, or hepatic steroid inactivating enzymes. We hypothesized that the induction of an accessory CL would decrease blood perfusion of the CL, decrease peripheral concentrations of progesterone, and increase clearance of progesterone in the liver. Total blood perfusion of the CL was increased in cows with 2 CL compared to cows with 1 CL, but concentrations of progesterone and hepatic enzymes did not differ. Overall, the increased blood perfusion in cows with 2 CL did not alter concentrations of progesterone or progesterone clearance.

Cows in first (n = 163) and second (n = 101) lactation were studied to determine if reproduction, progesterone (P4), IGF-I, insulin, NEFA, and milk production differed between genetic groups. Thirty-five cows were Holstein-Jersey (HJ) crosses, 48 were Jersey-Holstein (JH) crosses, 51 were Holsteins (HH), and 29 were Jerseys (JJ). Days open (DO) was affected by genetic group. HH had 168.6 ± 9.6 DO which was different from HJ (142.9 ± 11.3 d), JJ (132.1 ± 12.1 d), and JH (127.2 ± 9.3 d). HH had 2.4 ± 0.1 services per conception which was different from JH (1.9 ± 0.1), but not different from HJ (2.1 ± 0.2) or JJ (2.1 ± 0.2). In HH P4 concentrations (1.6 ± 0.11 ng/mL) were not different from HJ (1.5 ± 0.12 ng/mL), but lower than JH (1.8 ± 0.10 ng/mL) and JJ (1.8 ± 0.13 ng/mL). NEFA concentrations were greater in lactation 2 (0.52 ± 0.02 mEq/L) than in lactation 1 (0.45 ± 0.02 mEq/L). Insulin in HH (0.83 ± 0.03 ng/mL) was not different from HJ (0.87 ± 0.04 ng/mL) or JH (0.76 ± 0.03 ng/mL), but was greater than JJ (0.66 ± 0.04 ng/mL). IGF-I gradually increased over the 10 wk period. The HH produced 10,348 ± 208 kg of milk, which was greater than the HJ (9,129 ± 230 kg), the JH (9,384 ± 192 kg), and the JJ (7,080.9 ± 261 kg). Reproductive measures, milk yield, hormones and metabolites were affected by genetic groups. / Master of Science

In addition to their conventional role as hormones, studies have shown that steroids can act as pheromones in mammals. Emphasis has been placed on evaluating the physiological and behavioural effects of male, urinary 17β- estradiol (E2) exposure in pheromone phenomena including the prevention of embryo implantation and induced precocious puberty in females. Steroids have also been observed to transfer between female mice, leading to changes in the duration of their estrous cycle. Progesterone (P4), a crucial female sex steroid, promotes pro-social sexual reproductive behaviour and the growth of the endometrium in preparation for ovum implantation. Few studies have investigated the effects of P4 in a pheromonal context. Big brown bats (Eptesicus fuscus) are ideal models for pheromone research because they are evolutionarily distinct from rodents, live in highly social and sexually-competitive harems, and are regularly exposed to conspecific secretions in the close confines of their roost. Experimental analysis revealed absorption of tritium-labeled progesterone (3H-P4) (10 μCi) 1 h after cutaneous and intranasal application to adult females. Additionally, radioactivity was observed in mature female bats caged for 48 h with an adult female conspecific that had been intraperitoneally-injected with 3H- P4 (50 μCi). Using the same paradigm, 3H-E2 transfer was not observed between females. Enzyme-linked immunosorbent assays revealed measurable levels of unconjugated P4 and E2 present in the urine of female bats, suggesting urine as one likely vector for P4 transfer. Given corroborative findings in mice, progesterone transfer during cohabitation is likely a mammalian-wide phenomenon that could have evolved to prime conspecifics—and more specifically kin—for sexual reproduction. / Thesis / Master of Science (MSc) / Steroid molecules are conventionally assumed to act solely within the individual that produced them; however, recent experiments have demonstrated that the sex steroid 17β-Estradiol (E2) can be excreted in the urine of adult male mice and taken up into the neural, reproductive, and peripheral tissues of cohabitating females. This exogenous E2 can result in changes to female physiology and behaviour. Our lab has observed E2 to transfer between male and female captive big brown bats during the mating season. The current project aimed to determine whether E2 transfers between captive cohabitating female bats. We also examined whether progesterone (P4), an important female sex steroid involved in the preparation and maintenance of pregnancy, transfers between female bats. We determined that P4 reliably transfers between female bats, but E2 does not. Bioactive E2 and P4 were measured in the urine of non- pregnant female bats and propose urine as one likely vector of P4 transfer between cohabitating individuals.

No description available.

Le récepteur de la progestérone (PR) est un cible pharmacologique majeure pour la contraception, et pour le traitement de certaines pertubations endocriniennes ainsi que des cancers hormono-dépendants de l’utérus et du sein. Chez la femme, PR est exprimé sous deux isoformes majeures PRA et PRB qui sont des facteurs de transcription fonctionnellement distincts. L’expression de PRA vs PRB est souvent altérée dans certaines situations pathologiques selon des mécanismes encore mal identifiés. Dans cette thèse, nous démontrons que des phosphorylations clés regulées par des MAPK distincts contrôlent la stabilité de PRB et PRA. PRA est sélectivement stabilisée par la p38 MAPK tandis que PRB est préférentiellement stabilisé par la p42/44 MAPK. Ces mécanismes différentiels régulent donc le rapport d’expression PRA/PRB de façon ligand-dépendente et mettent les fonctions progestatives sous le contrôle de l’activité des facteurs de croissance et des cytokines pro-inflammatoires. Or, dans les cellules cancéreuses, la suractivité de certains stimuli extracellulaires provenant de telles signalisations et activant préférentiellement p42/44 et/ou p38 MAPK, pourrait être à l’origine des pertubations du rapport PRA/PRB observées dans les tumeurs du sein. Afin d’explorer la contribution différentielle des isoformes du PR dans la signalisation cellulaire, nous avons élaboré un modèle cellulaire original permettant de contrôler l’expression de PRA et/ou PRB de façon conditionnelle, réversible et dose-dépendante. Par une approche transcriptomique, nous avons identifiés les gènes régulés de façon différentielle par PRA et/ou PRB en absence ou présence de l’hormone. Nous montrons que plusieurs aspects de la signalisation de PR comme la sélectivité de la régulation transcriptionnelle, la dialogue-croisée avec des facteurs de croissance ainsi que l’efficacité antiproliférative des antiprogestatifs dépendent de l’expression differentielle des isoformes du PR. Une nouvelle approche thérapeutique ou préventive possible dans les cancers hormono-dépendants pourrait consister à administrer des antagonistes du PR. Cependant, la plupart des antiprogestatifs disponibles comme la mifépristone présentent des effets agonistes partiels et ne sont pas sélectifs du PR, produisant ainsi des effets indésirables majeurs. Dans un projet collaboratif, et sur la base d’études cristallographiques de PR, nous avons synthétisé et caractérisé plusieurs dizaines de molécules antagonistes du PR, nommés APRn. L’étude des relations structure-fonctions de ces APRn a permis d’identifier les substitutions introduites dans la structure stéroïdienne qui sont responsables des propriétés agonistes/antagonistes de ces molécules. Plusieurs APRn sélectionnés sont dépourvus d’effets agonistes partiels, sont spécifiques du PR et inhibent son activité transcriptionnelle par un nouveau mécanisme d’action dit « passif », en raison de leur capacité particulière à inhiber le recrutement des corégulateurs transcriptionnels. Ces antagonistes sélectifs de PR offrent des perspectives thérapeutiques intéressantes dans les maladies de la reproduction et des cancers hormono-dépendants de l’utérus et du sein. L’ensemble de nos résultats apportent des informations nouvelles sur les mécanismes impliqués dans la sélectivité fonctionnelle des isoformes du PR en physiopathologie, ainsi que sur la possibilité d’un ciblage pharmacologique spécifique par de nouveaux antagonistes utilisables dans le traitement du cancer du sein. / Progesterone receptor (PR) is an essential pharmacological target for contraception, female reproductive disorders as well as for hormone-dependent breast and uterine cancers. Human PR is expressed as two major isoforms PRA and PRB which behave as distinct transcriptional factors. PRA vs PRB expression is often altered under pathological conditions notably breast cancer through unknown mechanisms. In this thesis we demonstrate that down-regulations of PRB and PRA proteins are negatively controlled by key phosphorylation events involving distinct MAP kinase signaling. PRA is selectively stabilized by p38 MAPK whereas p42/44 MAPK specifically controls PRB stability leading to unbalanced PRA/PRB ratios in a ligand sensitive manner. In cancer cells, elevated extracellular stimuli such as epidermal growth factors or pro-inflammatory cytokines that preferentially activate p42/44 or p38 MAPK respectively may result in opposite variations in PRA/PRB expression ratio. These results may explain altered PRA/PRB ratios often associated with breast tumors. To get a mechanistic understanding of how varied PRA/PRB ratio contributes in cell signaling, we generated an original bi-inducible PR-isoform cell model allowing selective, reversible and dose-dependent expression of PRA and/or PRB, enabling fine-tune adjustment of PRA/PRB ratio in the same cells. Using this cell-based system, we undertook genome-wide transcriptomic studies to investigate transcriptional regulation driven by unliganded and liganded PR isoforms. We report that several aspects of PR signaling such as target gene selection/transcriptional regulation, cross-talk with growth factors and antiproliferative efficacy of antiprogestin are highly dependent upon variation in PRA/PRB ratio. A new potential therapeutic strategy in PR-dependent pathological conditions may rely on the use of PR antagonists. Most of the currently available antiprogestins such as mifepristone present partial agonist activity and are not selective to PR leading to undesirable side effects. Therefore, in a collaborative project we have synthesized and characterized several new PR antagonist compounds named as APRn. Structure-activity relationship studies allowed identification of the key substitutions in steroidal skeleton responsible for agonist/antagonist character of these molecules. Several selected APRn lack partial agonist effect, are PR specific and inhibit PR transcriptional properties through a new passive mechanism of action i.e. impaired recruitment of transcriptional coregulators. Such PR selective antagonists devoid of partial agonist character might provide important therapeutic perspectives for various reproductive tract abnormalities and hormone-dependent uterine and breast cancers. Altogehter, our results provide mechanistic insights into the functional selectivity of PR isoforms and their pharmacological targeting by the use of PR antagonists.