Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Restricted until October 2005. Bibliography: leaves 104-113.

Thesis (M. Sc. (Pharmacy))--Rhodes University, 2006.

O desenvolvimento embrionário tem inicio a partir da fecundação do oócito pelo espermatozóide no interior do oviduto. O oviduto é um órgão tortuoso que mede de 20 a 30cm e está dividido em três porções: istmo, ampola e infundíbulo. Os hormônios influenciam a atividade das células-alvo pela ligação de moléculas receptoras especificas. A imuno-histoquímica é o conjunto de procedimentos que utiliza anticorpos como reagentes específicos para detecção de antígenos presentes em células ou tecidos, portanto, através desta técnica é possível verificar a presença de receptores hormonais em determinados órgãos. Este estudo teve como objetivo localizar a presença de receptores para o hormônio luteinizante (LH) nas diferentes porções do oviduto utilizando a técnica de imuno-histoquímica. Foram utilizadas 18 éguas que se encontravam em estro, ou seja, apresentavam um folículo maior que 35mm e trato reprodutivo condizente com a fase estrogênica do ciclo estral. Das 18 éguas utilizadas neste trabalho, 16 éguas (88,8 %) apresentaram receptores para hormônio luteinizante (RLH) no oviduto. Destas 16 éguas, 8 (44,4 %) apresentaram RLH no epitélio e 7 (38,8 %) apresentaram RLH no tecido muscular do istmo, 14 (77,7 %) apresentaram RLH no epitélio e 13 (72,2 %) no tecido muscular da ampola, 10 (55.5 %) apresentaram RLH no epitélio e 1 (5,5 %) no tecido muscular do infundíbulo. Nas éguas que apresentaram receptores no epitélio a intensidade verificada foi de 1,5; 2,5 e 2,6 no istmo, ampola e infundíbulo, respectivamente enquanto que na porção muscular foi de 1,14; 2,3 e 3 respectivamente, para cada uma das três porções estudadas. Foi verificada uma maior intensidade de receptores na ampola do oviduto, o que pode relacionar o LH no processo de fecundação do oócito pelo o espermatozóide. / Embryonic development begins with the fertilization of the egg by the sperm in the oviduct. The oviduct is a tortuous organ which extended measures 20 to 30cm and is divided into three parts: the isthmus, ampulla and infundibulum. Hormones influence the activity of target cells by binding to specific receptor molecules. Immunohistochemistry is the set of procedures that use antibodies as reagents for detection of specific antigens present in cells or tissues, therefore, using this technique it is possible to verify the presence of hormone receptors in certain organs. This study aimed to verify the presence of hormone receptors for luteinizing hormone (LH) in different portions of the oviduct using the technique of immunohistochemistry. We used 18 mares were in estrus that had a follicle greater than 35mm and reproductive tract consistent with the estrogen phase of the estrous cycle. From the 18 mares that were part of that study, 16 mares (88.8 %) had receptors for luteinizing hormone (RLH) in the oviduct. From these 16 mares, 8 (44.4 %) had RLH in the epithelium and 7 (38.8 %) had RLH in the muscle of the isthmus, 14 (77.7 %) had RLH epithelium and 13 (72.2 %) in the muscle of the ampulla, 10 (55.5 %) had RLH in the epithelium m and 1 (5.5 %) in the muscle of the infundibulum. In mares that had receptors in the epithelium the intensity verified was 1,5 ; 2,5 and 2,6 on the isthmus, ampulla and infundibulum, respectively while in the muscular portion was 1,14 ; 2,3 and 3 respectively, for each of the three portions studied. It was verified a greater intensity of receptors in the ampulla of the oviduct, which may relate the LH in the process of fertilization of the oocyte by the sperm.

There is growing concern that the health of many species, including humans, may be threatened by an increasing burden of environmental contaminants. Many researchers around the world have made discoveries demonstrating endocrine activity in an array of contaminants to which humans and wildlife may be exposed. Although much of the focus has been upon interference with estrogen activities, there is growing evidence for interaction with thyroid, androgen and other endocrine axes. This study investigates the potential of a selection of environmental contaminants, including PCBs, pulp mill by-products, pesticides, and alkylphenols, to interfere with endocrine processes. Using tissue culture assays, we have investigated the ability of these compounds to interfere with steroid hormone signalling pathways and have focused on the underlying mechanism of androgenic effects observed through further in vitro assays. A transgenic mouse model was used to explore the impact of compounds of particular interest upon the development and function of androgen regulated tissues in vivo. Several of the test compounds possessed endocrine activity, most frequently manifest as antagonism of the androgen receptor (AR). Amongst the pesticides tested both the o,p′- and p,p′-isomers of dichlorodiphenyltrichloroethane (DDT) and p,p′-dichlorodiphenyldichloroethylene (DDE) were AR antagonists. Nonylphenol and a short chain ethoxylate (N-10) as well as four Aroclor mixtures and a set of congener components selected from them were also found to antagonise AR. Only hexachloroberizene and black liquor, a pulp mill by-product, exhibited androgenic effects in vitro . Estrogen receptor was antagonised by β-endosulfan and p,p′-DDE, while o,p ′-DDT, nonylphenol and octylphenol all acted as estrogen mimics. The glucocorticoid receptor was antagonised by β-endosulfan, while being stimulated by o,p′-DDT, the alkylphenol ethoxylate N-100 and PCB congener 42. Nonylphenol, Aroclor 1254 and one of the PCB congeners were tested by oral administration in mice and all produced physiological effects, with Aroclor 1254 in particular exhibiting clear anti-androgenic properties in vivo. Nonylphenol caused an elevation in serum thyroid hormone along with an increase in testis size and anogenital distance. In addition, the nonylphenol treatment increased the expression of an androgen responsive CAT reporter gene that is expressed specifically in the prostate. The PCB mixture Aroclor 1254 caused a decrease in prostate weight, and CAT reporter gene expression but precocious maturation of the prostate gland. In contrast the congener PCB 42 had no significant effects upon the prostate but caused increased testis weight and impacted on spermatogenesis in the epididymis. These results emphasize the sensitivity of the endocrine system and the diverse physiological functions which it regulates. They also demonstrate the ligand promiscuity of the steroid receptors and reinforce the need to evaluate the endocrine potential of substances humankind introduces into the environment. / Graduate

For my dissertation research I explored the diversity and functional evolution of steroid hormone receptors (SRs) in animals and the physiological implications of the evolution of antifreeze proteins in Antarctic notothenioid fishes. For the former, I discovered multiple new SRs from the vast and under-sampled swath of animal diversity known as invertebrates. I used the sequences of these and other newly discovered related receptors in combination with genomic data and molecular phylogenetic techniques to revise the understanding of the evolutionary history of this important gene family. While previous studies have suggested that vertebrate SR diversity arose from a gene duplication in an ancestor of all bilaterian animals, my work presents strong evidence that this duplication occurred much later, at the base of the chordates. Furthermore, to determine the implications of added diversity and a revised phylogeny on inferences of the functional evolution of SRs, I functionally characterized heretofore-unknown SRs from hemichordates, an acoelomate flatworm, and a chaetognath and statistically reconstructed and functionally characterized ancestral SRs. My results expand the known sequence and functional repertoire of SRs in animals while reinforcing the previous inference that all SRs evolved from an estrogen-sensitive ancestral receptor. I also explored the consequences of the evolution of antifreeze proteins in Antarctic notothenioid fishes, a crucial adaptation to their icy, polar environment. These special proteins adsorb to ice crystals that enter a fish's body and prevent further growth, thereby averting death. I discovered that, in addition to their lifesaving growth-inhibiting ability, AFPs also prevent the melting of internal ice crystals at temperatures above the expected equilibrium melting point. Together with a decade-long temperature record of one of the coldest fish habitats on earth, my experimental results show that the evolution and expression of antifreeze proteins is accompanied by a potentially detrimental consequence: the lifelong accumulation of ice inside these fishes' bodies. This dissertation includes previously published co-authored material as well as unpublished co-authored material. / 2017-01-14

Made available in DSpace on 2014-06-11T19:29:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2005Bitstream added on 2014-06-13T20:38:44Z : No. of bitstreams: 1 martin_i_me_botfmvz.pdf: 849389 bytes, checksum: 30bbc04c51aeac2ec027c75295df68f4 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Fundação para o Desenvolvimento da UNESP (FUNDUNESP) / Thirty Nelore cows were submitted to estrus synchronization using a single administration of lecirelina, at 25 mg dosage and seven days later, D+ Cloprostenol at, 0.15 mg being both administered intra-muscularly. The first 16 cows ovulating were selected and daily evaluation was performed by rectal palpation and ultrasound of the female reproductive tract followed by blood sampling. Endometrial samples were collected by biopsy at days 0, 5, 9, 13 and 19 of the estrous cycle to detect the presence of estrogen and progesterone receptors by immunohistochemistry. The cows were distributed in 3 groups: control (without endometrial sampling, n=8), D0 (sampling initiated at the day of ovulation, n=4) and D13 (sampling initiated at day 13 of the estrous cycle, n=4). The mean inter-estrus interval was 23.80 l 2.70. The progesterone plasma mean concentrations ranged from 0.06 ng/mL to 4.53 ng/mL, decreasing throughout the cycle and reaching the lowest value close to ovulation. The pattern was characterized by increasing values during the luteal phase. The estradiol 17-b mean concentrations ranged from 6.22 pg/mL to 14.10 pg/mL and these values did not change throughout the estrous cycle. The results obtained by the rectal palpation revealed that the uterine tone and thickness were changing throughout the estrous cycle, being elevated during the period close to ovulation, and they were decreased during the progesterone phase. The ultrasound demonstrates that the amount of fluid content on the cranial vaginal compartment and in the uterine horn lumen was modified throughout the cycle. The largest amount of fluid was observed during the closest period to estrus and small fluid accumulation was observed during the progesterone phase. However, cows that were submitted to endometrial sampling presented more fluid during the progesterone phase...