RESUMO
OBJECTIVE: To evaluate total testosterone (TT) kinetics and its predictors 6 months after the discontinuation of clomiphene citrate (CC) in patients with hypogonadism. MATERIALS AND METHODS: Consecutive patients with normal testicles and male hypogonadism defined by TT < 300 ng/dl in the presence of signs or symptoms according to the previous consensus were prospectively evaluated in a urologic outpatient clinic by TT levels at baseline (T0), after a daily dose of 50 mg CC for 40 days (T1), and after the washout period of 6 months of CC discontinuation (T2). RESULTS: Among 75 patients, mean age 56.8 years, testosterone at T1 > 300 ng/dl was achieved by 69 (92%), 450-600 ng/dl by 32 (42.6%), and > 600 ng/dl by 27 (36.0%). 18 subjects (24%) maintained asymptomatic and TT levels over 300 ng/dl at T2. Age negatively related to testosterone response and T1 response > 810 ng/dl predicts a median gain of 166.5 ng/dl at 6 months of CC discontinuation. CONCLUSIONS: CC is a compelling option to treat male hypogonadism, although a chronic treatment is needed in most patients. About one in every four patients respond to a CC short trial to "reboot" the physiology. Further understanding of TT kinetics in these patients in the long term is warranted.
Assuntos
Clomifeno , Hipogonadismo , Clomifeno/uso terapêutico , Humanos , Hipogonadismo/complicações , Hipogonadismo/tratamento farmacológico , Lactente , Cinética , Masculino , Pessoa de Meia-Idade , TestosteronaRESUMO
Over two-thirds of women with breast cancer have positive tumors for hormone receptors, and these patients undergo treatment with endocrine therapy, tamoxifen being the most widely used agent. Despite being very effective in breast cancer treatment, tamoxifen is associated with side effects that include cognitive impairments. However, the specific aspects and mechanisms underlying these impairments remain to be characterized. Here, we have investigated the effects of tamoxifen and interaction with estrogen receptors on formation of memory for inhibitory avoidance conditioning in female rats. In the first experiment, Wistar female rats received a single oral dose of tamoxifen (1, 3, or 10 mg/kg) or saline by gavage immediately after training and were tested for memory consolidation 24 h after training. In the second experiment, rats received a single dose of 1 mg/kg tamoxifen or saline by gavage 3 h after training and were tested 24 h after training for memory consolidation. In the third experiment, rats received a subcutaneous injection with estrogen receptor α agonist or estrogen receptor beta agonist 30 min before the training. After training, rats received a single oral dose of tamoxifen 1 mg/kg or saline and were tested 24 h after training. In the fourth experiment, rats were trained and tested 24 h later. Immediately after test, rats received a single dose of tamoxifen (1 mg/kg) or saline by gavage and were given four additional daily test trials followed by a re-instatement. Tamoxifen at 1 mg/kg impaired memory consolidation when given immediately after training and the estrogen receptor alpha agonist improved the tamoxifen-related memory impairment. Moreover, tamoxifen impairs memory consolidation of the test. These findings indicate that estrogen receptors regulate the early phase of memory consolidation and the effects of tamoxifen on memory consolidation.
Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Antagonistas do Receptor de Estrogênio/farmacologia , Receptor alfa de Estrogênio/metabolismo , Transtornos da Memória/induzido quimicamente , Tamoxifeno/farmacologia , Animais , Relação Dose-Resposta a Droga , Estrogênios/uso terapêutico , Extinção Psicológica/efeitos dos fármacos , Feminino , Consolidação da Memória/efeitos dos fármacos , Transtornos da Memória/tratamento farmacológico , Nitrilas/uso terapêutico , Fenóis/uso terapêutico , Propionatos/uso terapêutico , Pirazóis/uso terapêutico , Ratos , Ratos Wistar , Estatísticas não ParamétricasRESUMO
Evaluating the risk of breast cancer makes it possible to identify women with a high risk of developing breast cancer in the future. Adopting a healthier lifestyle, involving diet and exercise, is one way of reducing this risk-but there are other, non-modifiable risk factors, such as family history, genetics and diagnosis of premalignant lesions. In this high-risk population, the tracking must be rigorous and involve the participation of the patient herself, earlier and more frequent clinical assessment, and the use of imaging screening. Agents such as tamoxifen, raloxifene and aromatase inhibitors may be used in chemoprevention and may reduce the risk substantially. The risks and benefits must be assessed, and one must discuss with the patient her adverse events and the decision regarding the best treatment. Women who carry the BRCA1/2 mutation (very high risk) can benefit from prophylactic surgical interventions, such as bilateral mastectomy and/or bilateral salpingo-oophorectomy. This group of patients must be monitored by a multidisciplinary team, providing explanations prior to surgery regarding the surgical treatment offered, the reconstruction techniques, and the risks and complications.
RESUMO
Tamoxifen is effective in breast cancer therapy in postmenopausal women; however, it causes adverse effects that alter the glycolytic pathway and induce hyperglycemia. Quercetin, a flavonoid with antioxidant potential, inhibits butyrylcholinesterase (BuChE), which is positively associated with hyperglycemia. Therefore, this study investigated the effect of quercetin on tamoxifen-induced hyperglycemia, using BuChE activity as a bioindicator in adult ovariectomized Wistar rats. The ovariectomized rats were treated orally for 14 days with different concentrations of quercetin (2.5, 7.5, 22.5, and 67.5 mg.kg-1 b.w.) and tamoxifen (5 mg.kg-1 b.w.). Subsequently, they were euthanized; blood and tissue samples were collected. The following biochemical parameters were analyzed: plasma glucose levels and BuChE activity in the plasma, liver, intestine, and adipose tissue. The most effective dose of quercetin in reducing hyperglycemia was 22.5 mg.kg-1 b.w. (Que/TAM 4.5/1, P < .00000), although the doses of 2.5 (Que/TAM 0.5/1, P < .05) and 7.5 mg.kg-1 b.w. (Que/TAM 1.5/1, P < .05) were also effective. The BuChE activity decreased in the intestine at all tested doses of quercetin coadministered with tamoxifen (P < .01); however, in adipose tissue, there was a biphasic activity with a decrease (P < .05) and increase (P < .05) in activity at doses of 7.5 and 22.5 mg.kg-1 b.w. of quercetin, respectively. However, the correlation between BuChE and glucose levels was not significant (P > .05). In summary, the findings of the present study suggest that quercetin when associated with tamoxifen decreases in plasma glucose levels. Furthermore, in these cases, BuChE should not be used as an indicator of hyperglycemia.
Assuntos
Hiperglicemia/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Quercetina/administração & dosagem , Tamoxifeno/efeitos adversos , Animais , Antioxidantes/administração & dosagem , Butirilcolinesterase/metabolismo , Feminino , Glucose/metabolismo , Humanos , Hiperglicemia/etiologia , Hiperglicemia/metabolismo , Ovariectomia , Ratos , Ratos WistarRESUMO
Spinal cord injury (SCI) is a condition with no available cure. The initial physical impact triggers a cascade of molecular and cellular events that generate a nonpermissive environment for cell survival and axonal regeneration. Spinal cord injured patients often arrive at the clinic hours after the initial insult. This indicates the need to study and develop treatments with a long therapeutic window of action and multiactive properties, which target the complex set of events that arise after the initial trauma. We provide evidence that tamoxifen (TAM), a drug approved by the Food and Drug Administration, exerts neuroprotective effects in an animal model when applied up-to 24 h after SCI. We hypothesized that continuous TAM administration will improve functional locomotor recovery by favoring myelin preservation and reducing secondary damage after SCI. Adult female Sprague-Dawley rats (â¼230 g) received a moderate contusion to the thoracic (T9-T10) spinal cord, using the MASCIS impactor device. To determine the therapeutic window available for TAM treatment, rats were implanted with TAM pellets (15 mg) immediately or 24 h after SCI. Locomotor function (Basso, Beattie, Bresnahan open field test, grid walk, and beam crossing tests) was assessed weekly for 35 days post-injury. TAM-treated rats showed significant functional locomotor recovery and improved fine movements when treated immediately or 24 h after SCI. Further, TAM increased white matter preservation and reduced secondary damage caused by astrogliosis, axonal degeneration, and cell death after trauma. These results provide evidence for TAM as a potential therapeutic agent to treat SCI up to 24 h after the trauma.
Assuntos
Locomoção/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Recuperação de Função Fisiológica/efeitos dos fármacos , Traumatismos da Medula Espinal/complicações , Tamoxifeno/farmacologia , Animais , Feminino , Ratos , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/patologiaRESUMO
Selective estrogen receptor modulators (SERMs) have the ability to bind the estrogen receptor (ER) and are known to confer ER agonist or antagonist effects depending on the target tissue. A number of newer SERMs, including bazedoxifene, lasofoxifene and ospemifene, are currently under clinical development for the prevention and treatment of postmenopausal osteoporosis and for other indications. Although the possibility of developing a single agent that has all of the desired characteristics of an ideal SERM seems to be unlikely, progress in the clinical development of SERMs targeted to the ER suggests that these newer compounds may have attributes that represent an improvement relative to existing SERMs. A new approach to menopausal therapy is the tissue selective estrogen complex or the pairing of a selective estrogen receptor modulator with estrogens. Further investigation will help to clarify relative benefits/risks of novel SERMs in development within specific indications.
Moduladores seletivos do receptor do estrogênio (SERMs) têm a habilidade de se ligar ao receptor de estrogênio (ER) e são conhecidos por conferir um efeito agonista ou antagonista sobre o tecido-alvo. Um número de novos SERMs, incluindo bazedoxifeno, lasofoxifeno e ospemifeno, está atualmente em desenvolvimento clínico para prevenção e tratamento da osteoporose pós-menopausa e para outras indicações. Embora a possibilidade de desenvolver um simples agente que tenha todas as características desejadas de um SERM ideal parece ser pouco provável, esses novos SERMs apresentam propriedades que indicam uma melhora em relação aos SERMs existentes. Uma nova opção terapêutica é o uso do complexo estrogênico do tecido seletivo ou a associação do SERM com estrogênios. Novos estudos ajudarão a rastrear os riscos e benefícios dos novos SERMs em desenvolvimento dentro das suas indicações específicas.