The present investigation was designed to further our understanding of the interaction of pituitary (luteinizing hormone, LH) and placental (chorionic gonadotropin, CG) gonadotropins with the primate corpus luteum. Studies were performed (1) to characterize the LH/CG receptor population in the

Proteases of the plasminogen activator (PA) and the matrix metalloproteinase (MMP) enzyme systems are expressed in the ovulatory follicle and in the developing corpus luteum (CL). However, the functional role of these extracellular degrading protease systems in the ovulatory and CL development processes remains elusive. The first aim of this thesis was to develop a mouse model to study gonadotropin-induced CL formation. The second aim was to study the involvement of the PA and the MMP systems in gonadotropin-induced ovulation, and in CL formation and function. A mouse model for gonadotropin-induced CL formation was developed in order to control the timing of CL formation. In this model, immature mice were induced to ovulate by administrating gonadotropins and the endogenous prolactin surges were mimicked by administration of prolactin twice daily from day 2 of CL development. We observed that steroidogenic acute regulatory protein (StAR) mRNA was highly expressed at days 3 and day 6 of CL development and the levels remained high until late stages of CL regression. Since mice lacking plasminogen (plg-/-) only have a 14% reduction of ovulation efficiency, our hypothesis was that the MMP system could compensate for the loss of plasminogen. When administrating the MMP-inhibitor galardin to gonadotropin-primed ovulating mice, we found that wild-type mice (plg+/+ and C67BL/J6) and heterozygous mice (plg+/-) had an 18-20% reduction in ovulation efficiency as compared to untreated mice. Two models for CL formation, the adult pseudopregnant (psp) mouse model and a model whereby immature gonadotropin-primed mice were treated with prolactin, were used to study the formation and function of the CL in plg-/- mice treated with galardin. At day 3 of CL development, we found no alterations other than a slightly lower number of CL in plg-/- mice. This is most likely a secondary effect of the lower ovulation efficiency found in these mice. On the other hand, we found a 54% reduction in serum progesterone levels in plg-/- mice and a 37% reduction in the plg+/- mice as compared to wild type mice. At day 6 of CL development we saw a 45 % reduction of serum progesterone level in the plg-/- mice and a 22 % reduction in the plg+/- mice. A similar trend was observed at day 3 of CL development in immature gonadotropinprimed mice treated with prolactin. Galardin treatment did not alter the results significantly and the CLs were healthy and viable in these mice. In conclusion, our data suggest that both plasminogen and MMPs, alone or in combination, are dispensable for ovulation and for the formation of a viable CL under the conditions used in this study. The reduced serum progesterone levels observed in the plg-/- mice did not appear to be a result of defective CL formation. Instead, plasmin may have a novel role in the maintenance of luteal function. StAR expression may also be a good marker for CL development and regression in mice.

Thesis (Ph.D.)--University of Western Australia, 2003.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves [109]-132. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves [109]-132. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 148-171). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 148-171). Also available on the Internet.

Orientador: Joaquim Mansano Garcia / Coorientador: Naiara Saraiva Zoccal / Banca: Fábio Morato Monteiro / Banca: José Octavio Jacomini / Banca: Maria Emilia Franco Oliveira / Banca: Gilson Hélio Toniollo / Resumo: A progesterona e seus análogos têm sido utilizados para diversas finalidades na reprodução animal. O objetivo deste estudo foi avaliar a influencia da progesterona injetável no número de oócitos recuperados, na qualidade oocitária e produção embrionária de novilhas Nelore pré-púberes. Foram utilizadas 31 fêmeas com idade entre 18 a 20 meses, não gestantes e não cíclicas. As doadoras de oócitos foram divididas em 3 grupos experimentais em delineamento crossover da seguinte maneira: Grupo P0 (n=11), os animais deste grupo receberam duas aplicações de solução placebo (1 mL), com intervalo de 7 dias iniciando 14 dias (D-14) antes da primeira aspiração (D-0); Grupo P7 (n=10): os animais receberam uma aplicação de solução placebo (1 mL) 14 dias (D-14) e uma de progesterona (P4) injetável (150mg) 7 dias (D-7) antes da aspiração; Grupo P14 (n=10), neste grupo os animais receberam duas aplicações de P4 injetável (150mg) com intervalo de 7 dias, a primeira 14 dias (D-14) e a segunda 7 (D-7) dias antes da aspiração. Realizaram-se um total de três aspirações foliculares em intervalos de 28 dias. Os animais que apresentaram CL durante o experimento foram alocados em um grupo separado para serem analisados e comparados com o grupo sem CL. Os oócitos recuperados foram selecionados e submetidos aos procedimentos da PIVE. Após a confirmação da homocedasticidade (BoxCox) e normalidade (teste de Cramér-von Mises) dos dados, realizou-se a análise de variância (ANOVA). O teste de Tukey foi utilizado para as comparações das médias das variáveis, para as correlações dos dados foi utilizado o teste de correlação de Pearson, e significantes quando p≤ 0,05. Não foram verificadas diferenças significativas (p>0,05) quanto ao número de oócitos recuperados (oócitos totais), oócitos viáveis (G I, II, III), entre os animais tratados (grupos P7 e P14) em relação aos animais que não receberam P4 (grupo P0). As... / Abstract: Progesterone has been used for various purposes in the animal reproduction. The objective of this study was to evaluate the influence of exogenous progesterone injection in the number of recovered oocyte, oocyte quality and embryo production of prepubertal Nelore heifers. We used 31 females (18 to 20 months) non pregnant and without corpus luteum (CL). Cows were divided in 3 groups in a cross-over design: Group I P0 (n=11), animals received two placebo solution applications (1 mL), 7-day interval and starting 14 days (D-14) before the first aspiration (D-0); Group II P7 (n=10) treated group, the animals received a placebo solution application (1 mL) 14 days (D-14) and injecting progesterone (P4; 150 mg) 7 days (D-7) before aspiration; Group III P14 (n = 10), animals received two injections of P4 (150mμg) with an interval of 7 days, the first 14 days (D-14) and the second 7 days (D-7) before aspiration. We conducted 3 aspiration with 28-day intervals. The animals with CL during the experiment were placed in a separate group to be analyzed and compared with the group without CL. The recovered oocytes were selected and submitted to the procedures of the in vitro embryo production (IVEP). After confirming the homocedasticity (BoxCox) and normality (Cramér-von Mises test) of the data, carried out the analysis of variance (ANOVA). Tukey's test was used to compare the means of the variables and the pearson correlation test was used for correlations of the data, considered significant when p ≤ 0.05. There were no significant differences (p> 0.05) in the number of oocytes retrieved (total oocytes), viable oocytes (GI, II, III), between the animals treated (P7 and P14 groups) and animals that did not receive P4 (P0 group). The animals showed an average of 14.98 ± 10.82 oocytes collected by aspiration session. The mean and standard deviation of rates (%) of viable oocytes and embryos produced did not differ (p> 0.05) between groups. The ... / Doutor

Productivity efficiency in the livestock sector depends upon reproduction success at the farms. Evaluation of follicle and corpus luteum hemodynamics by color-Doppler ultrasonography is becoming more commonly used in cattle reproductive management. Improved understanding of the relationships between size and blood flow of the preovulatory follicle (POF) and corpus luteum (CL) with the subsequent systemic progesterone production, and the impact of those factors on fertility, would provide information to help maximize fertility in cattle reproduction. Three studies were conducted in this dissertation with the following general objectives: I) evaluate the relationships between follicle and corpus luteum dimensions and blood flow, and the influence of follicle size and wall blood flow on systemic progesterone production by the subsequent CL; II) study the relationships between follicle wall blood flow within different follicle size categories, between cows and heifers, and the effect on pregnancy rates; and III) develop a novel and reliable objective method for evaluation of follicle wall blood flow. In study one, high positive correlations were found among all POF and CL end points, and progesterone concentrations. Ratios of POF, CL, and progesterone end points ranged from moderate to strong positive correlations. Linear regression dispersions among selected POF and CL end points and progesterone concentrations showed high significance when using POF dimensions to estimate CL dimensions as well as POF blood flow to estimate CL size and blood flow, and plasma progesterone concentrations. In study two, cows had larger and more vascularized follicles than heifers. Pregnant cows had larger follicles and tended to have more vascularized follicles than non-pregnant cows. Follicle blood flow was greater in the large follicle category compared with the small follicles, and tended to be greater than medium-size follicles. Moderate to strong correlations were found between follicle blood flow and small, medium, and large follicles. Pregnancy rates were similar among follicle diameter categories. In study three, a novel objective method (wall under flow, WUF) for evaluation of follicle wall blood flow using color-Doppler ultrasonography was tested. Results indicated that due to differences in follicle morphology and in area and location of the blood flow, the objective pixel analysis previously reported in the literature for evaluation of CL blood flow cannot be translated as a gold standard test to objectively evaluate blood flow in follicles. The WUF was a superior method to evaluate follicle wall blood flow when compared with other methods. Furthermore, pixel area method did not sustain the validation of subjective evaluations of follicle wall blood flow. In conclusion, this work demonstrated novel linear relationships among POF and CL end points which can be used to estimate the subsequent progesterone production by the CL. Additionally, POF wall blood flow was closely associated with an increase in follicle diameter; smaller follicles had lower blood flow when compared with larger follicles. Moreover, the WUF was a more reliable method to objectively evaluate follicle wall blood flow in cows than the pixel area method.

Made available in DSpace on 2015-10-06T13:02:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-08. Added 1 bitstream(s) on 2015-10-06T13:19:16Z : No. of bitstreams: 1 000849551.pdf: 939514 bytes, checksum: 901efdf4cabd26a394b9aabd01d199d2 (MD5) / A progesterona e seus análogos têm sido utilizados para diversas finalidades na reprodução animal. O objetivo deste estudo foi avaliar a influencia da progesterona injetável no número de oócitos recuperados, na qualidade oocitária e produção embrionária de novilhas Nelore pré-púberes. Foram utilizadas 31 fêmeas com idade entre 18 a 20 meses, não gestantes e não cíclicas. As doadoras de oócitos foram divididas em 3 grupos experimentais em delineamento crossover da seguinte maneira: Grupo P0 (n=11), os animais deste grupo receberam duas aplicações de solução placebo (1 mL), com intervalo de 7 dias iniciando 14 dias (D-14) antes da primeira aspiração (D-0); Grupo P7 (n=10): os animais receberam uma aplicação de solução placebo (1 mL) 14 dias (D-14) e uma de progesterona (P4) injetável (150mg) 7 dias (D-7) antes da aspiração; Grupo P14 (n=10), neste grupo os animais receberam duas aplicações de P4 injetável (150mg) com intervalo de 7 dias, a primeira 14 dias (D-14) e a segunda 7 (D-7) dias antes da aspiração. Realizaram-se um total de três aspirações foliculares em intervalos de 28 dias. Os animais que apresentaram CL durante o experimento foram alocados em um grupo separado para serem analisados e comparados com o grupo sem CL. Os oócitos recuperados foram selecionados e submetidos aos procedimentos da PIVE. Após a confirmação da homocedasticidade (BoxCox) e normalidade (teste de Cramér-von Mises) dos dados, realizou-se a análise de variância (ANOVA). O teste de Tukey foi utilizado para as comparações das médias das variáveis, para as correlações dos dados foi utilizado o teste de correlação de Pearson, e significantes quando p≤ 0,05. Não foram verificadas diferenças significativas (p>0,05) quanto ao número de oócitos recuperados (oócitos totais), oócitos viáveis (G I, II, III), entre os animais tratados (grupos P7 e P14) em relação aos animais que não receberam P4 (grupo P0). As... / Progesterone has been used for various purposes in the animal reproduction. The objective of this study was to evaluate the influence of exogenous progesterone injection in the number of recovered oocyte, oocyte quality and embryo production of prepubertal Nelore heifers. We used 31 females (18 to 20 months) non pregnant and without corpus luteum (CL). Cows were divided in 3 groups in a cross-over design: Group I P0 (n=11), animals received two placebo solution applications (1 mL), 7-day interval and starting 14 days (D-14) before the first aspiration (D-0); Group II P7 (n=10) treated group, the animals received a placebo solution application (1 mL) 14 days (D-14) and injecting progesterone (P4; 150 mg) 7 days (D-7) before aspiration; Group III P14 (n = 10), animals received two injections of P4 (150mμg) with an interval of 7 days, the first 14 days (D-14) and the second 7 days (D-7) before aspiration. We conducted 3 aspiration with 28-day intervals. The animals with CL during the experiment were placed in a separate group to be analyzed and compared with the group without CL. The recovered oocytes were selected and submitted to the procedures of the in vitro embryo production (IVEP). After confirming the homocedasticity (BoxCox) and normality (Cramér-von Mises test) of the data, carried out the analysis of variance (ANOVA). Tukey's test was used to compare the means of the variables and the pearson correlation test was used for correlations of the data, considered significant when p ≤ 0.05. There were no significant differences (p> 0.05) in the number of oocytes retrieved (total oocytes), viable oocytes (GI, II, III), between the animals treated (P7 and P14 groups) and animals that did not receive P4 (P0 group). The animals showed an average of 14.98 ± 10.82 oocytes collected by aspiration session. The mean and standard deviation of rates (%) of viable oocytes and embryos produced did not differ (p> 0.05) between groups. The ...