commit 3fd3fc02becc016fc4e99fbdb822093ae62ca2ad Author: ferneg52177842 Date: Thu Apr 2 15:47:34 2026 +0800 Add 'On the trail of steroid aromatase: The work of Kenneth J Ryan' diff --git a/On-the-trail-of-steroid-aromatase%3A-The-work-of-Kenneth-J-Ryan.md b/On-the-trail-of-steroid-aromatase%3A-The-work-of-Kenneth-J-Ryan.md new file mode 100644 index 0000000..b5ef942 --- /dev/null +++ b/On-the-trail-of-steroid-aromatase%3A-The-work-of-Kenneth-J-Ryan.md @@ -0,0 +1,10 @@ +
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Nonaromatizable dihydrotestosterone is able to maintain or restore copulation in guinea pigs 101 and monkeys 102 suggesting that androgens are sufficient in these species. Moreover, men with congenital aromatase deficiencies are uniformly heterosexual 87, 88 and gene linkage studies in humans failed to suggest a role for aromatase variation in the development of sexual orientation in men 89. Structural sexual dimorphisms in the human brain have been described, but many of the reports are controversial and their functional significance is less well established than in animal models. More recent lesion studies suggest that the SDN is critical for male-typical sexual partner preferences in rats and ferrets 76, 77. The concept that in situ estrogen synthesis influences neural structures is well illustrated by the development of the sexually dimorphic nucleus (SDN) of the preoptic area of the rat 69. Much less is known about psychosexual differentiation in humans, but there is little evidence that aromatization is involved 46. have been undertaken on the relationship between more general aggressive behavior, and feelings, and testosterone. Nearly all studies of juvenile delinquency and testosterone are not significant. On the other hand, elevated testosterone in men may increase their generosity, primarily to attract a potential mate. Men who produce more [buy testosterone online](https://kjer-bendixen-4.technetbloggers.de/order-testosterone-cypionate-us-domestic-shipping-pay-with-bitcoin) are more likely to engage in extramarital sex. Men who produce less testosterone are more likely to be in a relationship or married, and men who produce more testosterone are more likely to divorce.|By doing so, individuals with masculinized brains are better able to survive and copulate with as many mates as possible. Studies conducted have found direct correlation between testosterone and dominance, especially among the most violent criminals in prison who had the highest testosterone. The first is the challenge hypothesis which states that testosterone would increase during puberty, thus facilitating reproductive and competitive behavior which would include aggression. There are two theories on the role of testosterone in aggression and competition. Studies have found that testosterone facilitates aggression by modulating vasopressin receptors in the hypothalamus.|This commission produced the Belmont Report in 1978, whose guidelines for protecting the rights and dignity of human subjects in research continue to provide an ethical framework for research and health providers in the United States to this day. "He actually got involved with a lot of ethical issues, like fetal tissue research," Auchus says. During a couple of residencies at hospitals in the Boston area, Ryan landed a biochemistry fellowship shared with Nobel Laureate Fritz Lipmann, enabling him to pursue his interest in the roles of estrogens in the biology of pregnancy. These discoveries underscored the utility of Ryan's assay and represented key early steps in untangling the biochemical complexities in estrogen production. He also clarified that another estrogen, 16α-hydroxyestrone, is an intermediate in the classic estriol-producing pathway (3). Using his placental microsomal enzyme system, Ryan confirmed his earlier finding of estriol production from 16α-testosterone.} +In addition, the amount of testosterone produced by existing Leydig cells is under the control of LH, which regulates the expression of 17β-hydroxysteroid dehydrogenase. The number of Leydig cells in turn is regulated by luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In the final and rate limiting step, the C17 keto group androstenedione is reduced by 17β-hydroxysteroid dehydrogenase to yield testosterone. In contrast to testosterone, DHEA and DHEA sulfate have been found to act as high-affinity agonists of these receptors. In the bones, estradiol accelerates ossification of cartilage into bone, leading to closure of the epiphyses and conclusion of growth. As a result, testosterone which is not bound to SHBG is called free testosterone. The part of the total hormone concentration that is not bound to its respective specific carrier protein is the free part. +In short gestation species (i.e. rodents), there is a peak in both activity and mRNA expression of aromatase in the preoptic area/hypothalamus that occurs late in gestation or early neonatal life and corresponds to the critical period for sexual differentiation 3. Because of the diverse age- and region-specific actions of testosterone, it is not surprising that the regulation of aromatase in the brain is complex and not completely understood. This latter possibility is supported by reports showing that the incidence of aromatase and estrogen receptor localization is not absolute but ranges from 5% to 80% depending on specie and brain area 19–21. This endocrine brain circuit contains an overlapping distribution of androgen- and estrogen-receptor containing cells 8. +Women's level of testosterone is higher when measured pre-intercourse vs. pre-cuddling, as well as post-intercourse vs. post-cuddling. Men who watch sexually explicit films also report increased motivation and competitiveness, and decreased exhaustion. This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction. Therefore, these mammals may provide a model for studying clinical populations among humans with sexual arousal deficits such as hypoactive sexual desire disorder. Sexual arousal and masturbation in women produce small increases in testosterone concentrations. Regular monitoring during treatment typically includes hematocrit levels every 3-6 months to prevent polycythemia, along with PSA monitoring in men over 40. +Implementing strategies such as maintaining a healthy body weight, following a balanced diet, and incorporating regular exercise can help support hormonal balance and optimize your fitness outcomes. For more serious hormonal imbalances, aromatase inhibitors (AIs) may be prescribed to reduce estrogen production. Losing fat—especially visceral fat—can lower estrogen levels and improve the testosterone-to-estrogen ratio (Cleland et al., 1985). In both sexes, estrogen supports connective tissue resilience, which reduces injury risk during high-intensity exercise or weight training (Torres et al., 2021). +Is there a genetic component to aromatase activity and estrogen levels? While no single food can drastically lower estrogen levels, certain foods may support a healthy hormonal balance. The primary strategy for reducing estrogen levels in obese males is weight loss through lifestyle modifications. The balance between testosterone and estrogen is critical for male health. The more fat tissue a person has, the more aromatase they possess, leading to a higher rate of testosterone conversion to estrogen. Aromatization is the conversion of androgens, like testosterone, into estrogens, such as estradiol (E2). +When supplemental testosterone enters your body, an enzyme called aromatase converts a portion of it into estrogen. Total levels of testosterone in the body have been reported as 264 to 916 ng/dL (nanograms per deciliter) in non-obese European and American men age 19 to 39 years, while mean testosterone levels in adult men have been reported as 630 ng/dL. 5α-Reductase is highly expressed in the male reproductive organs (including the prostate gland, seminal vesicles, and epididymides), skin, hair follicles, and brain and aromatase is highly expressed in adipose tissue, bone, and the brain. Approximately 5 to 7% of testosterone is converted by 5α-reductase into 5α-DHT, with circulating levels of 5α-DHT about 10% of those of [buy testosterone supplements](https://hack.allmende.io/s/9Zck4ccK0), and approximately 0.3% of testosterone is converted into estradiol by aromatase. When testosterone levels are low, gonadotropin-releasing hormone (GnRH) is released by the hypothalamus, which in turn stimulates the pituitary gland to release FSH and LH. +Polymorphisms in the CYP19A1 gene can result in higher or [https://pads.jeito.nl/s/QlUNpSYwbI](https://pads.jeito.nl/s/QlUNpSYwbI) lower enzyme activity, influencing how much estrogen is produced from testosterone. It helps maintain the balance between androgens and estrogens, both of which play vital roles in male and female physiology (Simpson et al., 2002). Aromatization occurs through the enzymatic activity of aromatase (CYP19A1), which is present in various tissues including adipose tissue, the liver, and the gonads. Without aromatization, the body would struggle to maintain the hormonal equilibrium necessary for these critical functions. +
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