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Basic medicine: physiology
Published in Roy Palmer, Diana Wetherill, Medicine for Lawyers, 2020
The gonads comprise the ovaries in the female and the testes in the male. Each gonad has a dual function: to produce germ cells, i.e. ova and spermatozoa, and to secrete sex hormones. Pituitary hormones (gonadotropins) cause enlargement of the ovary and testis during childhood, and the resultant release of gonadal hormones brings about the changes of puberty, including the growth spurt and the secondary sexual characteristics of females and males. Oestrogens and progesterone secreted by the ovary cause girls to start their monthly cycle of ovulation and menstruation, while testicular androgens stimulate the production of fertile sperm and seminal fluid. If sexual intercourse takes place during the period following ovulation, when an ovum is shed from the ovary and passes down the female genital tract, then conception may take place as the sperm penetrates the ovum. The developing embryo implants into the wall of the uterus, leading to the formation of the placenta, and placental hormones then sustain the pregnancy. At birth, which occurs around 270 days later, pituitary oxytocin governs the onset of uterine contractions. The breasts have enlarged during pregnancy under the combined actions of oestrogen, progesterone and the pituitary hormone prolactin. After birth lactation is controlled by prolactin combined with oxytocin secreted as a reflex response to suckling by the infant.
Hormone replacement therapy and endometrial cancer
Published in A. R. Genazzani, Hormone Replacement Therapy and Cancer, 2020
C. W. Burger, G. A. van Unnik, P. Kenemans
The role of endogenous gonadal hormones in the etiology of endometrial cancer is much better understood than it is for breast and ovarian cancer. The mitotic activity of endometrial tissue has been shown to be highest in the follicular phase of the menstrual cycle when estrogen levels are high20. Any factor that lowers exposure of the endometrium to estrogens, or increases progesterone levels, decreases the risk of endometrial cancer, whereas any factor causing prolonged exposure of the endometrium to ‘unopposed’ estrogen tends to raise the risk. Anovulation, infrequent ovulations and various progesterone deficiencies generally characterize hormonal subfertility. Irregular (long) menstrual cycles are often anovulatory, or have a prolonged follicular phase. Both features result in prolonged exposure to ‘estrogen unopposed by progesterone’, and would thus be expected to raise the risk of endometrial cancer21. Obviously, progesterone deficiency also results in prolonged exposure to ‘unopposed’ estrogen. Similarly, fertility drugs that prolong exposure of the endometrium to ‘unopposed’ estrogen might increase the risk of endometrial cancer.
Neurohypophyseal Hormones and Reproductive Hormone Secretion
Published in Craig A. Johnston, Charles D. Barnes, Brain-Gut Peptides and Reproductive Function, 2020
Finally, it has been known for a long time that the secretion of reproductive hormones from the anterior pituitary is greatly influenced by changes in the plasma levels of gonadal hormones, and this influence may be mediated, in part, by OXY and/or AVP neurons. For example, although LHRH neurons are greatly influenced by plasma estradiol concentrations, no binding of estradiol on LHRH neurons has yet been identified. On the other hand, subpopulations of OXY neurons demonstrate nuclear receptors for estradiol (Sar and Stumpf, 1980; Dufau and Catt, 1978), and may represent the anatomical loci for such an important link. The influence of estradiol on these systems and the potential importance of the gonadal hormones to these interactions will be expanded throughout this chapter.
Is chronic pain as an autoimmune disease?
Published in Canadian Journal of Pain, 2022
Sex differences have a biological basis and are undoubtedly complex. Sex-associated steroids cause activation of some pain responses and analgesic efficacy in adults. Perinatal dimorphisms in testosterone levels produce enduring organizational differences in males and females. Various lines of evidence support that immune-triggered conditions exhibit a sex bias in children prior to the onset of puberty,83,84 and therefore it is important to explore facets other than gonadal hormones to understand sex differences in chronic pain. In addition to the action of sex hormones on nociceptive circuits, genes mapping to the X and Y chromosomes are considered to be important players, with the neuroendocrine system modulating the effects stemming from the sex chromosome complement. Hence, research in chronic pain, from a patient perspective, will require fundamentally improving therapeutic interventions to provide precision medicine for feamales and males. It potentially may require the direct manipulation of gonadal hormones in relevant female and male animal models at different life stages. This will be important to determine how hormonal and sex chromosomal influences interact to modulate the neuroimmune system. It will provide a better fundamental understanding of their roles in the development, maturation, and dysregulation of nociceptive circuits.
Safety and tolerability of progesterone treatment for women with cocaine use disorder: a pilot treatment trial
Published in The American Journal of Drug and Alcohol Abuse, 2022
Alyssa Oliva, Stephanie C. Reed, Daniel J. Brooks, Frances R. Levin, Suzette M. Evans
Overall, this pilot study demonstrates that oral micronized progesterone was well-tolerated and safe for women with CUD. With respect to reductions in cocaine use, oral micronized progesterone did not reduce cocaine use relative to the placebo group. These findings are similar to several previous laboratory studies that failed to show a reduction in cocaine self-administration when progesterone was administered (11,12). The present study also points out the challenges in engaging women with CUD for treatment. Despite the small sample size, in conjunction with previous successful clinical trials examining progesterone for smoking cessation, these findings suggest that additional study is needed in a larger sample to determine if progesterone may be an effective treatment option for increasing days to cocaine relapse for women with CUD. Further, there continues to be an interest regarding the utility of progesterone and other gonadal hormones as treatments for substance use disorders and the results of exogenous progesterone appear to be more promising for women than men (39).
The effect of different contraceptive methods on the vaginal microbiome
Published in Expert Review of Clinical Pharmacology, 2021
Carlo Bastianelli, Manuela Farris, Paola Bianchi, Giuseppe Benagiano
Such a system is strongly influenced by gonadal hormones and a just published meta-analysis [25], involving approximately 1,000 VM samples, tried to evaluate temporal changes, correlations between hormonal changes and VM and the effect of dysbiotic conditions. The investigation placed in a comprehensive context structural variation of the VM across a woman’s life-span, revealing the existence of temporal trends in vaginal microbial community diversity. It also showed significant differences in the VM overall diversity in various reproductive and post-reproductive phases. Finally, it highlighted the role of gonadal hormones in maintaining a healthy VM, showing that its perturbation can contribute and even cause a serious imbalance. The study puts forward a ‘hormone-level driven microbiome diversity’ hypothesis for explaining temporal patterns during various stages of a woman reproductive cycle and following menopause. Results reinforced the concept that gonadal hormones play a pivotal role in maintaining gynecological health and indicated that hormonal level perturbations contribute to imbalances in VM [25].