Modulation of spermatozoon acrosome reaction [Biological Research, 44, 151–159]
Author: Vigil, P., Orellana, R. F., & Cortés, M. E. (2011)
Spermatozoon acrosome reaction is an exocytotic event of the utmost importance for the development of mammalian fertilisation. Current evidence shows that the triggering of the acrosome reaction (AR) could be regulated by the action of diverse compounds, namely, metabolites, neurotransmitters and hormones. The aim of the present review is to describe the modulating effects of several compounds that have been classified as inductors or inhibitors of acrosome reaction. Among AR inductors, it is necessary to mention progesterone, angiotensin II, atrial natriuretic peptide, cathecolamines, insulin, leptin, relaxin and other hormones. Regarding the inhibitors, oestradiol and epidermal growth factor are among the substances that retard AR. It is worth mentioning that gamma-aminobutyric acid, a neurotransmitter known to be an inhibitor in the central nervous system, has been shown to induce AR. The multiple hormones located in the fluids of the female reproductive tract are also likely to act as subtle regulators of AR, constituting a fundamental aspect for the development of successful fertilisation. Finally, it is necessary to emphasise that the study of regulation exerted by hormones and other compounds on AR is essential for further understanding of mammalian reproductive biology, especially spermatozoon physiology.
Endocrine Modulation of the Adolescent Brain: A Review [Journal of Pediatric and Adolescent Gynecology, 24, 330–337]
Author: Vigil, P., Orellana, R. F., Cortés, M. E., Molina, C. T., Switzer, B. E., & Klaus, H. (2011)
Neurophysiological and behavioral development is particularly complex in adolescence. Youngsters experience strong emotions and impulsivity, reduced self-control, and preference for actions which offer immediate rewards, among other behavioral patterns. Given the growing interest in endocrine effects on adolescent central nervous system development and their implications on later stages of life, this article reviews the effects of gonadal steroid hormones on the adolescent brain. These effects are classified as organizational, the capacity of steroids to determine nervous system structure during development, and activational, the ability of steroids to modify nervous activity to promote certain behaviors. During transition from puberty to adolescence, steroid hormones trigger various organizational phenomena related to structural brain circuit remodelling, determining adult behavioral response to steroids or sensory stimuli. These changes account for most male-female sexual dimorphism. In this stage sex steroids are involved in the main functional mechanisms responsible for organizational changes, namely myelination, neural pruning, apoptosis, and dendritic spine remodelling, activated only during embryonic development and during the transition from puberty to adolescence. This stage becomes a critical organizational window when the appropriately and timely exerted functions of steroid hormones and their interaction with some neurotransmitters on adolescent brain development are fundamental. Thus, understanding the phenomena linking steroid hormones and adolescent brain organization is crucial in the study of teenage behavior and in later assessment and treatment of anxiety, mood disorders, and depression. Adolescent behavior clearly evidences a stage of brain development influenced for the most part by steroid hormones.
Usefulness of Monitoring Fertility from Menarche [Journal of Pediatric and Adolescent Gynecology, 19(3), 173–179]
Author: Vigil, P., Ceric, F., Cortés, M. E., & Klaus, H. (2006)
The concept of the ovarian cycle as a continuum considers that all types of ovarian activity encountered during the reproductive life are responses to different environmental conditions in order to ensure the health of the woman. During the normal ovulatory cycle, a series of sequential events have to occur in a highly synchronized manner. Fertility awareness is useful in helping women to identify the different stages of their reproductive life cycle. Fertility awareness is also a valuable tool in helping women to identify gynecological disorders. Persistence of irregularities within the mucus patterns and the menstrual cycle should be of concern to women presenting with these problems. These irregularities may be due to obstetrical, endocrine, gynecological or iatrogenic disorders. Insight into early pregnancy complications, ovulatory dysfunction and pelvic inflammatory disease can be ascertained from abnormalities within the menstrual cycle and mucus pattern. Thus, fertility awareness will also enable the recognition and early treatment of several metabolic, endocrine and infectious diseases.
Types of ovarian activity in women and their significance: the continuum (a reinterpretation of early findings) [Human Reproduction Update, 17(2), 141–58]
Author: Brown, J. B. (2010)
There are many types of ovarian activity that occur in women. This review provides information on the relationship between the hormone values and the degree of biological response to the hormones including the frequency and degree of uterine bleeding. The continuous process is termed the ‘Continuum’ and is thus similar to other processes in the body.
The role of kisspeptin on the onset of puberty and on the ovulatory mechanism: A minireview [Journal of Pediatric and Adolescent Gynecology, 28(5), 286–291]
Author: Cortés, M. E., Carrera, B., Rioseco, H., del Río, J. P., & Vigil, P. (2015).
The onset of puberty has been a fascinating topic for reproductive endocrinologists for decades; however, its underlying physiological mechanisms have remained elusive until recently. The discovery and understanding of the effects exerted by the peptide hormone kisspeptin have shed light on this research area. This review is aimed to discuss the functions of kisspeptin, with special focus on its role in the onset of puberty and in the ovulatory mechanism. The points under discussion are (1) the characteristics of kisspeptin and its receptor, (2) the relevance of this hormone and its interaction with leptin in the onset of puberty, (3) the role of kisspeptin in the ovulatory mechanism based on its differential expression at hypothalamic nuclei, which is modulated by sex steroid hormones, and (4) the clinical relevance of kisspeptin and its antagonists in new therapeutic strategies for the treatment of various reproductive pathologies. All of this explains the revolution that kisspeptin has caused among researchers working in the field of gynecological endocrinology and reproductive biology.
The effects of hormonal contraceptives on glycemic regulation [The Linacre Quarterly, 81(3), 209–218]
Author: Cortés, M. E., & Alfaro, A. a. (2014)
A number of side effects have been linked to the use of hormonal contraceptives, among others, altera- tions in glucose levels. Hence, the objective of this mini-review is to show the main effects of hormonal contraceptive intake on glycemic regulation. First, the most relevant studies on this topic are described, then the mechanisms that might be accountable for this glycemic regulation impairment as exerted by hormonal contraceptives are discussed. Finally, we briefly discuss the ethical responsibility of health pro- fessionals to inform about the potential risks on glycemic homeostasis regarding hormonal contraceptive intake.
Highly symmetrical crystallization in six rectilinear and well- defined axes found in bovine cervical mucus obtained at oestrus: a finding. [Revista de La Facultad de Medicina Veterinaria y de Zootecnia, 61(2), 167-170]
Author: Cortés, M. E., González, F., Hauyón, R., & Vigil. Pilar. (2014)
Bovine cervical mucus (BCM) is important for selection and transport of spermatozoa. When air-dried, BCM obtained at oestrus exhibits arborescent crystallizations, among other arrangements. Considering the relevant endocrine and reproductive information indirectly obtained from BCM crystallization, a morphological investigation was carried out to study its crystalline patterns. BCM samples were collected from healthy Holstein Friesian heifers at oestrus, their crystalline patterns photographed and its morphology analyzed. The majority of the crystallizations obtained showed the typical tree-like patterns reported for BCM. However, a highly symmetrical arrangement was found, characteri- zed by a star-like morphology with six straight, highly defined axes that protrude from the same central point, forming 60o angles. In terms of current knowledge, this short report is the first to show this crystallization geometry in BCM, which, additionally, is remarkably similar to P6B mucus reported for periovulatory human cervical mucus. Even though the role of mucus presenting this type of crystallization is as yet unknown for bovines, its possible functions are also briefly discussed here.