Diet-induced obesity promotes type 2 diabetes (T2D). Drugs that inhibit the renin-angiotensin system (RAS) have been demonstrated in clinical trials to decrease the onset of T2D. Previously, we demonstrated that mice made obese from chronic consumption of a high-fat (HF) diet have marked elevations in systemic concentrations of angiotensin II (AngII). Pancreatic islets have been reported to possess components of the renin-angiotensin system (RAS), including angiotensin type 1a receptors (AT1aR), the primary receptor for AngII, and angiotensin converting-enzyme 2 (ACE2), which negatively regulates the RAS by catabolizing AngII to angiotensin-(1-7) (Ang-(1-7)). These two opposing proteins have been implicated in the regulation of β-cell function. We hypothesized that the RAS contributes to the decline of β-cell function during the development of T2D with obesity. To test this hypothesis we first examined the effects of whole-body deficiency of ACE2 in mice on β-cell function in vivo and in vitro during the development of T2D. Whole-body deficiency of ACE2 resulted in impaired β-cell adaptation to insulin resistance with HF-feeding and a reduction of in vivo glucose-stimulated insulin secretion (GSIS) associated with reduced β- cell mass and proliferation. These results demonstrate that ACE2 plays a role in the adaptive response to hyperinsulinemia with obesity. In islets from HF-fed mice, AngII inhibited GSIS. In mice with pancreatic-specific deletion of AT1aR, AngII-induced inhibition of GSIS in vitro from islets of HF-fed mice was abolished. However, there was no effect of pancreatic AT1aR-deficiency on glucose homeostasis in vivo in HF-fed mice exhibiting pronounced hyperinsulinemia. Notably, pancreatic weight, insulin content and basal and glucose-stimulated insulin secretion from islets were decreased in mice with pancreatic AT1aR deficiency. These results suggest that AT1aR may contribute to pancreatic cell development, and also contribute to AngII-induced reductions in GSIS from islets of HF-fed mice. Overall, these studies suggest a role for the RAS in the regulation of β-cell function in T2D.

Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease with no available pharmacological treatment. AAA formation reduces the structural integrity of the vessel and increases the susceptibility to rupture. The inflammatory response within human aneurysmal tissue is characterized by increased expression of cyclooxygenase-2 (COX-2). Similarly, in a mouse model of the disease induced by chronic Angiotensin II (AngII) infusion, we have shown that COX-2 expression in the abdominal aortic smooth muscle layer increases early in the development of the disease. Furthermore, genetic or pharmacological inactivation of COX-2 prior to disease initiation reduces AAA incidence. The current study utilized nonhyperlipidemic mice to determine the effectiveness of COX-2 inhibition initiated after AAA formation. COX-2 inhibitor treatment was initiated 5 days after beginning the AngII infusion, a time-point where significant aneurysmal pathology is observed. COX-2 inhibition with celecoxib significantly reduced the incidence as well as severity of AAAs as compared to the control group. Celecoxib treatment also protected the mice from aortic rupture and death. AAA development is characterized by degradation of the aortic smooth muscle layer with loss of the contractile phenotype. We found that the effectiveness of celecoxib was associated with significantly increased mRNA expression of alpha-actin, SM22alpha and desmin, all of which are markers of a differentiated smooth muscle cell phenotype. Celecoxib treatment also decreased mRNA expression of a marker of dedifferentiated smooth muscle (hyaluronic acid synthase 2). We also examined the role of altered expression of COX-2 in the increased susceptibility of the abdominal segment to AAA formation. We found a prolonged and greater induction of COX-2 in the abdominal aortic smooth muscle layer in contrast to a transient induction of COX-2 in the other regions of the aorta throughout disease progression. Overall, these findings suggest that COX-2 plays an important role in AAA development in mice, and COX-2 inhibition with celecoxib attenuates progression of aneurysm development by maintaining a differentiated phenotype in abdominal aortic smooth muscle cells.

Abdominal aortic aneurysm (AAA) is a disease of the aorta characterized by pathological remodeling and progressive weakening of the vessel resulting in the increased risk of rupture and sudden death. In a mouse model of the disease induced by chronic Angiotensin II (AngII) infusion, progression of AAAs is associated with reduced differentiation of smooth muscle cells (SMCs) at the site of lesion development. In the mouse model, the effectiveness of cyclooxygenase-2 (COX-2) inhibition for attenuating AAA progression is associated with maintenance of a differentiated SMC phenotype. However, the safety of COX-2 inhibitors is currently in question due to the increased risk of adverse cardiovascular events. Thus, it is crucial to identify mediators downstream of COX-2 that may provide new targets for treatment of this disease. Recent studies in humans and mouse models have suggested that the microsomal prostaglandin E synthase (mPGES-1) enzyme, which acts downstream of COX-2, may also be involved in the pathogenesis of the disease. We hypothesized that increased prostaglandin E2 (PGE2) synthesis resulting from the induction of both COX-2 and mPGES-1 may result in reduced differentiation of SMCs, and that disruption of this pathway would preserve the differentiated phenotype. To test this hypothesis, human aortic smooth muscle cells (hASMCs) were utilized to examine the effects of a variety of agents involved in AAA development and the COX-2 pathway. My findings suggest that one of the effects of exposing hASMCs to AngII involves a specific induction of mPGES-1 expression. Furthermore, although different COX-2-derived products may have opposing effects, mPGES-1-derived PGE2 may be the primary prostanoid synthesized by SMCs which functions to attenuate differentiation. Therefore, mPGES-1 inhibition may provide inhibition of PGE2 that is more specific than COX-2 inhibitor treatment and may serve as a therapeutic target for attenuating AAA progression by maintaining a differentiated SMC phenotype.

Angiotensin II (AngII), the major effector of the renin angiotensin system, mediates kidney disease progression by signalling through AT-1 receptor (AT-1R), but there are no specific measures of renal AngII activity. Accordingly, we sought to define an AngII-regulated proteome in primary human proximal tubular cells (PTEC) in order to identify potential AngII activity markers in the kidney. We utilized stable isotope labelling with amino acids (SILAC) in PTECs to compare proteomes of AngII-treated and control cells. Of 4618 quantified proteins, 83 were differentially regulated. SILAC ratios for 18 candidates were confirmed by Selected Reaction Monitoring (SRM) assays. Both SILAC and SRM revealed the nuclear factor erythroid 2-related 2 (Nrf2) target protein, heme oxygenase-1 (HO-1) as the most significantly upregulated protein in response to AngII stimulation. AngII-dependent regulation of HO-1 gene and protein was further verified by qRT-PCR and ELISA in PTECs. In order to extend these in vitro observations, we utilized a systems biology approach. We thus overlaid a network of significantly enriched gene ontology (GO) terms from our AngII-regulated proteins with a dataset of differentially expressed kidney genes from AngII-treated wild type mice and AT-1R knock-out mice. Five GO terms were enriched both in vitro and in vivo, and all included HO-1. Furthermore, four additional Nrf2 target proteins were functionally important in vitro and in vivo. We then studied HO-1 kidney expression and urinary excretion in AngII-treated wild type mice and mice with PTEC-specific AT-1R gene deletion. Deletion of the AT-1R gene in PTECs lowered both kidney expression and urine excretion of HO-1, confirming AngII/AT-1R mediated regulation of HO-1. In summary, our in vitro experiments identified novel molecular markers of AngII activity in PTECs and the animal studies demonstrated that these markers also reflect AngII activity in PTECs in vivo. These interesting proteins hold promise as specific markers of renal AngII activity in patients and in experimental models.

Non invasive in vivo imaging will lead to better understanding of Angiotensin II Type 1 Receptor’s (AT1R) role in disease progression and may guide therapy in cardiovascular patients. Two models were used in this project: 5/6 nephrectomy and transient left anterior descending (LAD) ligation. Rats were scanned with [13N]ammonia and [11C]methyl-candesartan, both of which are Positron Emission Tomography (PET) tracers, at 8 weeks (nephrectomy) and 2 weeks (LAD ligation) after surgery. Western blot analysis was used to corroborate PET data. Nephrectomy: Renal AT1R image analysis displayed a 40% decrease in kidney AT1R in nephrectomized animals compared to sham (p<0.05) which was confirmed with Western blot and biodistribution. LAD ligation: Left Ventricle AT1R Western blot analysis exhibited a 60% increase in 20min ligation (p<0.05) with maintained myocardial blood flow. In conclusion, changes in renal AT1R were successfully imaged using [11C]methyl-candesartan in nephrectomized animals, and 20min LAD ligation/reperfusion is an appropriate model to image an increase in cardiac AT1R following ischemic injury.

Orientador: Marcos Renato de Assis / Resumo: A expectativa de vida diminui com artrite reumatoide (AR) devido ao aumento da mortalidade por doenças cardiovasculares. Isto se deve, possivelmente, à disfunção endotelial resultante da intensa atividade inflamatória relacionada à AR. Evidências tem apontado para um possível envolvimento do sistema renina-angiotensina (SRA) nos danos cardiovasculares inerentes à AR. Acredita-se que a participação do SRA agrave o comprometimento endotelial decorrente de inflamações sistêmicas através da ativação do receptor de angiotensina II tipo 1 (AT1) pela angiotensina II (Ang II). Por outro lado, a literatura também reporta a influência dos hormônios andrógenos, principalmente da testosterona, nas ações da Ang II sobre os tecidos vasculares. Assim, o objetivo do presente estudo é investigar os efeitos da artrite induzida por adjuvante (AIA) sobre o equilíbrio redox, a função endotelial e as respostas da aorta de ratos à Ang II, bem como, verificar se esses efeitos podem ser influenciados pela redução dos níveis circulantes de testosterona. Para isto, ratos Wistar machos adultos foram submetidos à falsa-castração e falsa-imunização (Controles), castração seguida de falsa-imunização (ORX), falsa-castração seguida de imunização (ORX) e castração seguida de imunização (ORX+AIA). Ao final do experimento, segmentos de aorta torácica foram desafiadas em cubas de órgãos isolados com acetilcolina (ACh), Ang II, KCl e nitroprussiato de sódio e, das curvas concentração resposta obtidas, calculou-se... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Life expectancy of patients with rheumatoid arthritis (RA) is lower due to increased mortality in consequence of cardiovascular diseases. Presumably, this occurs due to endothelial dysfunction resulting from severe inflammatory activity related to RA. Evidence has demonstrated a possible involvement of the renin-angiotensin system (RAS) in the cardiovascular injury inherent to RA. The RAS involvement is considered to worsen the endothelial impairment due to systemic inflammation through angiotensin II type 1 receptor (AT1) activation of Ang II. (Ang II). Additionally, previous studies also observed that androgen hormones, mainly the testosterone, modulate the Ang II actions in cardiovascular tissues. Thus, the aim of the present study is to investigate the effects of adjuvant-induced arthritis (AIA) on systemic redox balance, endothelial function and rat aorta responses to Ang II, as well as, whether these effects may be influenced by the reduction of circulating levels of testosterone. For this, adult male Wistar rats were submitted to false-castration and false-immunization (Controls), castration followed by false-immunization (ORX), false-castration followed by immunization (ORX) and castration followed by immunization (ORX + AIA) . At the end of the experiment, thoracic aorta segments were challenged in isolated organ bath with acetylcholine (ACh), Ang II, KCl and sodium nitroprusside and, from the concentrantion-response curves obtained were calculated pEC50 and maximal ... (Complete abstract click electronic access below) / Doutor

A hipertensão cursa com importante déficit autonômico e lesão da barreira hematoencefálica (BHE) enquanto que o treinamento aeróbio (T) de hipertensos reduz acentuadamente a lesão da BHE, mantendo sua integridade no PVN, NTS e RVLM mesmo na persistência de níveis pressóricos elevados. Esta rápida resposta ao T (2 semanas) é condicionada pela redução da disponibilidade de ANGII nas áreas encefálicas, simultâneo aumento da expressão de podócitos dos astrócitos e desativação da microglia, os quais ocorrem simultaneamente à redução do simpático vasomotor (2 semanas) e antes mesmo do aumento da variabilidade da frequência cardíaca, da atividade parassimpática ao coração, da instalação da bradicardia de repouso e queda parcial da pressão arterial, que se instalam a partir da 4ª semana de T. Alterações na permeabilidade da BHE de hipertensos (lesão com prejuízo estrutural/funcional) e treinados (manutenção da integridade estrutural/funcional) são importantes fatores a condicionar respectivamente a disfunção autonômica na hipertensão ou a sua correção pelo treinamento. / The arterial hypertension is accompanied by important autonomic dysfunction and blood-brain barrier (BBB) lesion while aerobic training (T) in hypertension strongly decreases the BBB lesion, maintaining its integrity on the PVN, NTS and RVLM even in the persistence of high blood pressure (BP) levels. This early response to T (2 weeks) is conditioned by the reduction of ANGII availability, increased expression of astrocytic podocytes and deactivation of the microglia in brain areas. These responses occurred simultaneously with the reduction of vasomotor sympathetic activity (2 weeks) and before the increase of both heart rate variability and parasympathetic activity, resting bradycardia and partial BP fall, appearing only at the 4th week. Changes on the BBB permeability in hypertension (lesion with structural/functional damage) and trained (maintenance of the structural/ functional integrity) are important factors to condition the autonomic dysfunction in hypertension or its correction by the training, respectively.

Estudos anteriores de literatura indicavam que o sistema renina-angiotensina II local pineal era de fundamental importância para a expressão plena da capacidade de síntese de melatonina induzida pela estimulação noradrenérgica pelos pinealócitos. Essa relação funcional estava na dependência de uma interação parácrina entre pinealócitos e astrócitos onde os astrócitos seriam os responsáveis pela síntese de angiotensina II que, liberada pela ação da noradrenalina, agiria em receptores do tipo AT1 existentes na membrana dos pinealócitos. O objetivo desse trabalho foi o de, uma vez estabelecida a metodologia de dissociação e cultivo dos tipos celulares, estudar a hipótese acima, além das possíveis vias de transdução intrapinealocitárias que levassem ao efeito potenciador da angiotensina II sobre a estimulação noradrenérgica no processo de síntese de melatonina. Os resultados mostraram que, diferentemente do que acontece com glândulas intactas ou com co-cultura (cultura contendo astrócitos e pinealócitos), a estimulação noradrenérgica de pinealócitos isolados não é passível de bloqueio por Losartan, uma droga bloqueadora de receptores AT1. Por outro lado, nas mesmas condições experimentais, a síntese de melatonina induzida pela estimulação noradrenérgica é passível de potenciação pela adição de angiotensina II , efeito esse, que é bloqueado pelo Losartan. Demonstrou-se, ainda, que a estimulação noradrenérgica de astrócitos isolados, provoca a liberação de angiotensina II por esse tipo celular. Demonstrou-se, ainda, que há a mobilização de pelo menos duas vias de transdução nos pinealócitos quando estimulados pela angiotensina II: aumento da concentração de cálcio intracelular e mobilização de processos de fosforilação em tirosina usando as vias das proteínas JAK/ STAT. Dessa forma, pelo presente trabalho pode- se especular que quando a glândula pineal é estimulada pela liberação de noradrenalina dos terminais simpáticos, ao mesmo tempo que esta age nos pinealócitos promovendo a via de síntese de melatonina, age, também, nos 7 astrócitos, liberando angiotensina II que, por sua vez, age nos pinealócitos potenciando a ação estimulatória da noradrenalina, levando a um aumento da síntese de melatonina. / We have previously demonstrated that Angiotensin II (Ang II) potentiates the noradrenaline-stimulated (Nor+) melatonin synthesis in the rat pineal gland [Baltatu et al.,J. Neurochem.(2002)80, 328-334]. The aim of the present paper was to study the possible paracrine interactions between glial cells and pinealocytes in the rat pineal gland. To accomplish this aim, after standard pineal cell dissociation we studied the two cellular types separated in different cell cultures, either of glial pineal cells or pinealocytes. First, we showed, using freshly dissociated pineal cells, that Losartan is able to reduce Nor+ induced melatonin synthesis, similarly to what happens with pineal glands culture. Noradrenaline stimulation is able to induce melatonin synthesis in glial cell-free pinealocytes cell culture, what is not blocked by Losartan. In this condition, Ang II is able to potentiated the Nor+ induced melatonin synthesis, an AngII effect that is blocked by Losartan. Moreover, Ang II stimulated pinealocytes show an increase in Ca2+ current as evaluated by confocal microscopy. On the other hand, pinealocytes-free glial cells cultures when stimulated by noradrenaline release Ang II in the culture medium. Taking into account the above results it is possible to speculate that in the intact pineal gland noradrenaline released by sympathetic terminals stimulated pinealocytes inducing the well know process of melatonin synthesis at the same time that stimulate glial cells that release AngII that acting through AT1 receptors in pinealocytes potentiate melatonin synthesis by the inducing an increase in the intracellular Ca2+ pool and tyrosine phosphorylation of JAK/STAT complex.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objectives of this study were: to determine the presence of prorenin and the receptor of (pro)renin [(P)RR] in cumulus cells (CC) and oocytes; evaluate the role of prorenin in the resumption of oocyte meiosis, ovulation and on levels of plasma progesterone (P4). The mRNA expression of prorenin and (P) RR was evaluated in oocytes and cumulus cells of the bovine species. The mRNA of prorenin and (P)RR was detected in CC, in oocytes only mRNA expression of (P)RR was found. The role of prorenin in the resumption of meiosis was determined from 3 experiments using a co-culture of cumulus-oocyte complex (COC) and follicular halves. In the first experiment, three different concentrations of prorenin (10-10, 10-9, and 10-8M) were tested, which stimulated the resumption of meiosis similar to the positive control and angiotensin II (Ang II). In experiment 2, the co-culture was supplemented with prorenin (10-10M) and aliskiren (direct inhibitor of renin, 10-3M, 10-5M and 10-7M). The aliskiren blocked the resumption of meiosis-induced by prorenin in all concentrations tested. The aliskiren (10-5M and 10-7M) was also evaluated in isolation in a culture system of COCs without follicular halves and the rate of oocytes that resumed meiosis was not different of the positive control. The third experiment was conducted to evaluate the stimulation of meiosis resumption by prorenin independent of Ang II using the combination of prorenin (10-10M) and saralasin [nonspecific Ang II receptor antagonist - Sar (10-5M)], which obtained a rate of oocytes at metaphase I (MI) similar to the positive control and treatments of AngII and prorenin. The prorenin also resumed the oocyte meiosis in a culture system of COCs suplemmented with forskolin, wicth blocks the meiosis by intracellular cAMP accumulation. To evaluate the regulation of (P)RR mRNA in the theca and granulosa cells by LH, cows who achieved follicular diameter ≥12mm after synchronization were submitted to the ovariectomy 0, 3, 6, 12 and 24 hours after GnRH analogue treatment. There was a higher mRNA expression of (P)RR in the theca cells at hour 6; and at hour 3 in the granulosa cells. The effect of (P)RR in ovulation and plasma P4 during luteinization was observed cows that were synchronized and induced by GnRH analogue (IM) associated for intrafollicular aliskiren (10-5M) or PBS (0hour/0day) and the ovulation was evaluated at 24, 48 and 72 hours by ultrasound, wicth was not different of the control (PBS). The leves of plasma P4 was analysed at day 6 and 8 after GnRH and intrafollicular treatment only in the cows that ovulated. The intrafollicular (P)RR blocks decreased plasma P4 at day 6. It was concluded that the prorenin / (P)RR participates in the peri-ovulatory period: in the resumption of oocyte meiosis independently of AngII, in the ovulation by LH stimulation to (P)RR mRNA and in the P4 synthesis during luteinization. / Os objetivos deste estudo foram: determinar a presença de prorenina e receptor de (pro)renina [(P)RR] nas células do cumulus (CC) e em oócitos; avaliar o papel da prorenina na retomada da meiose oocitária; na ovulação e sobre os níveis de progesterona plasmática (P4). A expressão do RNAm de prorenina e (P)RR foi avaliada em oócitos e CC da espécie bovina. O RNAm de prorenina e (P)RR foi detectado nas células do cumulus; nos oócitos ocorreu apenas expressão de RNAm de (P)RR. O papel da prorenina na retomada da meiose foi determinado a partir de 3 experimentos utilizando um sistema de co-cultivo de complexo-cumulus oócito (COC) e metades foliculares. No primeiro experimento, foram testadas três concentrações de prorenina (10-10; 10-9; e 10-8M), as quais estimularam a retomada da meiose semelhante ao controle positivo e angiotensina II (Ang II). No experimento 2, o co-cultivo foi suplementado com prorenina (10-10M) e alisquireno (inibidor direto de renina; 10-3M, 10-5M e 10-7M). O alisquireno bloqueou a retomada da meiose induzida pela prorenina em todas concentrações testadas. O alisquireno (10-5M e 10-7M) também foi avaliado isoladamente em sistema de cultivo de COC sem metades foliculares e a taxa de oócitos que retomaram a meiose não diferiu do controle positivo. O experimento 3 foi realizado para avaliar o estímulo da retomada da meiose pela prorenina independente da Ang II utilizando a associação de prorenina (10-10M) e saralasina [antagonista do receptor da Ang II - Sar (10-5M)], a qual obteve taxa de oócitos em metáfase I (MI) semelhante ao controle positivo e aos tratamentos AngII e prorenina. A prorenina também retomou a meiose oocitária em cultivo de COCs suplementado com forskolin, que bloqueia a meiose pelo acumulo de AMPc intracelular.Para avaliar a possível influência do pico de LH na expressão do RNAm de (P)RR nas células da teca e granulosa, vacas que apresentaram folículo ≥12mm de diâmetro após a sincronização farmacológica do ciclo estral foram ovariectomizadas 0, 3, 6, 12 e 24 horas após aplicação do análogo do GnRH. Houve maior expressão de RNAm de (P)RR nas células da teca na hora 6; e na hora 3 nas células da granulosa. O papel do (P)RR na ovulação e sobre a P4 plasmática durante a luteinização foi verificado em vacas sincronizadas farmacológicamente, induzidas pelo análogo de GnRH (IM) associado ao alisquireno (10-5M) ou PBS intrafolicular (hora 0/ dia 0) e foram avaliadas por ultrason 24, 48 e 72 horas quanto a ovulação, a qual não diferiu do controle (PBS). Os níveis de P4 plasmática foram analisados nos dias 6 e 8 após GnRH e tratamento intrafolicular apenas nas vacas que ovularam, nas quais o bloqueio de (P)RR reduziu P4 no dia 6. Concluiu-se que a prorenina/(P)RR participa do periodo peri-ovulatório: na retomada da meiose oocitária de forma independente da AngII, na ovulação pelo estímulo de LH sobre RNAm do (P)RR e na síntese de P4 durante a luteinização.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Many studies have been developed to characterize the function of angiotensin-renin system (ARS) in the female reproductive organs. Evidences from the literature have pointed a relevant role of angiotensin II (Ang II) in mammals, through its type 2 receptor (AT2) in oocyte maturation as in ovulation. Nevertheless, the participation of Ang II in other important reproductive features such as steroidogenesis has not been fully clarified. Therefore, the main objective of this work was to detect in vitro the steroidogenic effects of Ang II in theca cells. For that, bovine theca cells were obtained from follicles (larger than 8mm of diameter) collected from a local abattoir and submitted to different treatments in a sequence of experiments. In Experiment 1, Ang II was added to LH-treated (10 ng/ml) theca cells. Experiment 2 employed Ang II, in different concentrations, in addition to insulin (100 ng ̸ml) and LH (100 ng ̸ml). Experiment 3 explored the effects of an Ang II antagonist (saralasin) in theca cells co-stimulated by insulin and LH (both at 100 ng ̸ml). After 24 hours, culture media were collected and evaluated for testosterone and androstenedione levels measured by high performance liquid chromatography (HPLC). In parallel, gene expression of key steroidogenic enzymes and proteins, respectively, HSD3B2, CYP11A1 e CYP17A1 and STAR were accessed by qRT-PCR, with exception of experiment 1, in which only CYP17A1 was evaluated. Overall, absence of Ang II action was observed in all Ang II doses evaluated. Despite the difference in gene expression for CYP17A1 against controls in experiment 1, neither an increase in androgens levels nor a negative impact of saralasin were detected. Although very important for oocyte maturation and the ovulation, Ang II seems not influence androgen production by theca cells in vitro. In conclusion our results do not support the role for Ang II in thecal steroidogenesis, at least in bovine, as the primary hypothesis of the study. / Diversos estudos vêm sendo desenvolvidos para caracterizar o sistema renina angiotensina (RAS) no aparelho reprodutivo feminino. Evidências da literatura apontam um importante papel da angiotensina II (Ang II), via receptor tipo 2 (AT2), tanto na maturação dos oócitos quanto na ovulação em mamíferos. No entanto, a participação da Ang II em outros aspectos reprodutivos importantes, como a esteroidogênese, ainda não foi completamente elucidada. Desta forma, o objetivo deste trabalho foi verificar o efeito in vitro da Ang II nas células da teca cultivadas. Para isso, células da teca bovina foram obtidas de folículos com mais de 8mm de diâmetro de ovários oriundos de abatedouro local e submetidas a diferentes tratamentos em uma sequência de experimentos. No experimento 1, Ang II foi adicionada a células da teca tratadas com LH na dose de 10 ng/ml. No experimento 2, foi utilizada Ang II em diferentes concentrações em adição ao tratamento com insulina (100 ng ̸ml) e LH (100 ng ̸ml). O experimento 3, explorou o possível efeito de um antagonista da Ang II (saralasina) em células da teca co-estimuladas com insulina e LH (ambos em 100 ng ̸ml). Após 24 horas, o meio de cultura foi coletado e avaliado para verificação dos níveis de testosterona e androstenediona aferidos pela técnica de cromatografia líquida de alta performance (HPLC). Em paralelo, a expressão gênica de enzimas e proteínas chaves na esteroidogênese, respectivamente, HSD3B2, CYP11A1 e CYP17A1 e STAR, foram avaliadas por qRT-PCR, com exceção do experimento 1 onde somente a CYP17A1 foi estudada. De maneira geral, não foi observada uma ação da Ang II nas doses utilizadas. Apesar de uma diferença na expressão de CYP17A1 ter sido verificada em relação aos controles, nem o aumento dos níveis de androgênios ou um impacto negativo pelo uso de saralasina foram detectados. Embora reconhecida como muito importante para maturação oocitária e ovulação, a Ang II parece não influenciar a produção de androgênios in vitro. Em conclusão, nossos resultados não demonstraram um papel da Ang II na esteroidogênese tecal, pelo menos na espécie bovina, ao contrário da hipótese original deste estudo.