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Tamoxifen, a selective non-steroidal estrogen receptor modulator, is the standard adjuvant endocrine treatment for breast cancer. Since information on the risk of using tamoxifen during pregnancy is still scarce, this study evaluated whether the in utero and lactational treatment with this drug could compromise reproductive and behavioural parameters in male offspring. Pregnant Wistar rats were exposed to three doses of tamoxifen (0.12; 0.6; 3 µg/kg), by gavage, from gestational day 15 to lactational day 20. Tamoxifen exposure did not alter the anogenital distance in the male offspring; however, there was a significant increase in the body weight in the 0.12 µg/kg dose and a decrease in the 0.6 µg/kg dose. The male offspring treated with the highest dose exhibited a delay in the onset of puberty, evidenced by an increase in the age of preputial separation. Regarding sperm parameters, there was an increase in the sperm count in the cauda epididymis in the intermediate and highest dose groups, in addition to an increase in the number of static sperm and a decrease in the progressive sperm in the same groups. Moreover, an increase in the number of hyperplasia of the epithelial clear cells was observed in the epididymis. In conclusion, the present study demonstrated that maternal exposure to tamoxifen compromised the installation of puberty of the male offspring and the maturation of the epididymis, affecting sperm storage and motility in the adult life.

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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 (∼230 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.

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Tamoxifen has been shown to be active in vitro against Leishmania and effective in the treatment for leishmaniasis in murine models. Through the screening of a compound library of estrogen receptor modulator analogs, we identified the major characteristics required for antileishmanial activity. To overcome the difficulties presented by tamoxifen's propensity for E/Z isomerization, we used the 2-arylbenzothiophene compound BTP as a more stable alternative. Directed screening of a small compound library based on BTP led to active compounds against Leishmania. Subsequent structure-activity data for the synthetic 2-arylbenzothiophenes evaluated in this study indicate that optimal antileishmanial potency is dependent on the presence of two basic side chains. In addition, the primary structural features required for estrogen receptor binding, the phenols, are not required for inhibiting parasitic growth. Significantly, the most active antileishmanial benzothiophenes lack the pharmacophore for estrogen receptor activity and therefore address potential concerns about the undesirable effects of using selective estrogen receptor modulators in women and children with leishmaniasis. Three compounds selected from the screening have shown consistent activity against all species and stages of Leishmania in vitro although improvements in selectivity are needed. These compounds represent viable starting points for further optimization as antileishmanial agents.

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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.

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