Archives

  • 2018-07
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04

    • br Acknowledgement Work in the

    2023-02-06


    Acknowledgement Work in the McEwan Laboratory is funded by the Chief Scientist Office of Scottish Government: Grants ETM-258 and ETM-382. BE is supported by an Erasmus scholarship (D -JENA01).
    Introduction The equine placenta is a noninvasive transient organ, classified as diffuse and epitheliochorial [1]. It supplies the fetus with necessary nutrients and gasses and removes fetal waste. Additionally, the placenta possesses endocrine, paracrine, and autocrine capabilities [2], [3]. The placenta is involved with supplying hormones and growth factors required for fetal growth and maintenance of pregnancy while also being influenced by hormones of both maternal and fetal origin [4]. Known equine placental hormone receptors include the alcohol dehydrogenase inhibitor receptors ESR1 and ESR2, and progesterone receptors PR-A and PR-B [5]. Although androgen receptors (ARs) have been identified in the placenta of other species, such as human, cattle, and rats, no such reports are present for the horse [6], [7], [8], [9]. The identification of hormone receptors in the placenta is critical for understanding how hormones influence placental and fetal development, as well as their contribution to pregnancy problems and placental abnormalities. In an effort to determine the exact role of androgen on the placenta in the horse, we must first determine if AR is present in the placenta. In this study, we hypothesized that, like other species, AR is present in the equine placenta.
    Materials and Methods
    Results
    Discussion Hormones play an important role in many aspects of pregnancy, including placental development and function. Although the placenta acts as an autocrine, endocrine, and paracrine organ, little is known about how or which hormones regulate its function and development [4]. Many hormone receptors are present in the placenta across species, but research is limited in the horse. For example, expression of AR has been confirmed in the placentas of several species, including human, cattle, and sheep; however, evidence is lacking for the horse [4], [6], [8], [10]. At the conclusion of this study, our results confirmed the expression of AR in the equine placenta by both mRNA and protein of the term equine placenta via reverse transcription PCR and Western blot analysis, respectively. Although estrogen and progesterone are the most commonly referenced hormones involved in pregnancy, studies indicate that testosterone levels in the plasma of a pregnant mare peak at 10 times the basal level at around 7 months of gestation [11]. This correlates with the development of fetal gonads and their increasing production of dehydroepiandrosterone, which is then converted to estrogens by the placenta [11], [12], [13], [14], [15], [16]. Although the exact function of this increased testosterone remains unknown, ovine studies indicate that these act directly through ARs to induce multiple effects on the placenta and fetus [10], [17]. For example, ovine studies have indicated that an artificial increase in testosterone during gestation results in low birth weight, advanced placental differentiation, and intrauterine growth retardation [10], [18]. Furthermore, AR is possibly involved in placental angiogenesis. In human studies, increased levels of androgens such as testosterone have multiple effects on increased expression of estrogen and ARs, abnormal placental development and morphology, as well as decreased fetal weight [7]. Therefore, it is clear that androgens and their placental receptors play a key role in the development and function of the placenta. By proving the presence of ARs in the equine placenta, we provide new insight into the possible existence of androgen signaling in the equine placenta. However, further studies are required to identify the exact role that ARs play throughout pregnancy in the horse.
    Acknowledgments
    Introduction Cadmium (Cd) is a human carcinogen (i.e. lung cancer) and a potential risk factor for prostate cancer [1]. Findings from epidemiological studies [[2], [3], [4]], however, are inconsistent and have resulted in Cd rarely being listed among the more accepted prostate cancer risk factors, which include older age, African American race, family history of the disease, and living in a westernized nation [5]. A better understanding of the potential pathways through which Cd may act in prostate carcinogenesis could lead to improvements in epidemiological study design that may produce more consistent findings between Cd exposure and prostate cancer in humans.