Estrogen regulated DNA repair mechanisms in the brain have neuroprotective effects. Allowed for by estrogen, progesterone and prolactin work together to complete lobuloalveolar development during pregnancy. Estrogen is primarily and directly responsible for inducing the ductal component of breast development, as well as for causing fat deposition and connective tissue growth. Since estrogen enters all cells, its actions are dependent on the presence of the ER in the cell. Testosterone increases bone density and tells the bone marrow to manufacture red blood cells. Testosterone replacement therapy comes with a few potential side effects, including acne and breast enlargement. The voice begins to deepen, and muscles and body hair grow. Men who have prostate or breast cancer should not consider testosterone replacement therapy. There's more to testosterone than guys behaving badly. For example, did you know that testosterone is a key player in prostate cancer? When you think of testosterone, what comes to mind? It also affects mental health, bone and muscle mass, fat storage, and red blood cell production. There’s a wide range of normal or healthy levels of testosterone circulating in the bloodstream. It also affects bone and muscle mass, the way men store fat in the body, and even red blood cell production. Seven studies were eventually included in the systematic review (Table 1), and all of them showed beneficial impacts on a range of health outcomes, including depression, vascular endothelial function, muscle strength, bone health, and sexual function. Additionally, testosterone supports endothelial function by increasing nitric oxide production, encouraging endothelial cell growth and repair, and lowering inflammation; it also has a significant impact on the vascular endothelium, the thin layer of cells lining blood vessels, which is essential for preserving cardiovascular health . The increase in sex steroid production during puberty speeds up bone mineral accumulation and causes sex-specific variations in bone growth; after mid-puberty, the male population experiences a greater increase in periosteal bone growth than the female population, who shows more pronounced endocortical bone formation . As a primary hormone influencing bone metabolism, testosterone directly affects osteoclasts, osteoblasts, and osteocytes, promoting periosteal bone formation during puberty and decreasing bone resorption during adulthood; testosterone is also strongly correlated with bone density; lower testosterone levels result in decreased bone density . The actions of estrogen are mediated by the estrogen receptor (ER), a dimeric nuclear protein that binds to DNA and controls gene expression. Estrogens are among the wide range of endocrine-disrupting compounds and can cause health issues and reproductive dysfunction in both wildlife and humans. Once inside the cell, they bind to and activate estrogen receptors (ERs) which in turn modulate the expression of many genes. In addition, what may seem like a symptom of testosterone excess (see below) may actually be unrelated to this hormone. While the specifics are uncertain, it's possible that androgens also play an important role in normal brain function (including mood, sex drive and cognitive function). A "feedback loop" closely regulates the amount of hormone in the blood. Signals sent from the brain to the pituitary gland at the base of the brain control the production of testosterone in men. The brain is also affected by this sexual differentiation; the enzyme aromatase converts testosterone into estradiol that is responsible for masculinization of the brain in male mice. Some of these effects may decline as testosterone levels might decrease in the later decades of adult life. The male brain is masculinized by the aromatization of testosterone into estradiol, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected. Among women with congenital adrenal hyperplasia, a male-typical play in childhood correlated with reduced satisfaction with the female gender and reduced heterosexual interest in adulthood. As the metabolism of testosterone in males is more pronounced, the daily production is about 20 times greater in men. It’s natural for testosterone levels to vary depending on your age and overall health. Late-onset male hypogonadism happens when the decline in testosterone levels is linked to general aging and/or age-related conditions, particularly obesity and Type 2 diabetes.
