Estrogen in the context of "Selective estrogen receptor modulator"

Castration is any action, surgical, chemical, or otherwise, by which a male loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharmaceutical drugs to deactivate the testes. Some forms of castration cause sterilization (permanently preventing the castrated person or animal from reproducing); it also greatly reduces the production of hormones, such as testosterone and estrogen. Surgical castration in animals is often called neutering.

Castration of animals is intended to favor a desired development of the animal or of its habits, as an anaphrodisiac or to prevent overpopulation. The parallel of castration for female animals is spaying. Castration may also refer medically to oophorectomy in female humans and animals.

Pubic hair (or pubes /ˈpjuːbiːz/, /pjuːbz/) is terminal body hair that is found in the genital area and pubic region of adolescent and adult humans. The hair is located on and around the sex organs, and sometimes at the top of the inside of the thighs, even extending down the perineum, and to the anal region. Pubic hair is also found on the scrotum and base of the penile shaft (in males) and on the vulva (in females). Around the pubis bone and the mons pubis that covers it, it is known as a pubic patch, which can be styled.

Although fine vellus hair is present in the area during childhood, pubic hair is considered to be the heavier, longer, coarser hair that develops during puberty as an effect of rising levels of hormones: androgens in males and estrogens in females.

Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell.

For example, endogenous substances, and endogenous processes are those that originate within a living system (e.g. an organism or a cell). For instance, estradiol is an endogenous estrogen hormone produced within the body, whereas ethinylestradiol is an exogenous synthetic estrogen, commonly used in birth control pills.

Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) in a standard regimen. Chemotherapy may be given with a curative intent (which almost always involves combinations of drugs), or it may aim only to prolong life or to reduce symptoms (palliative chemotherapy). Chemotherapy is one of the major categories of the medical discipline specifically devoted to pharmacotherapy for cancer, which is called medical oncology.

The term chemotherapy now means the non-specific use of intracellular poisons to inhibit mitosis (cell division) or to induce DNA damage (so that DNA repair can augment chemotherapy). This meaning excludes the more-selective agents that block extracellular signals (signal transduction). Therapies with specific molecular or genetic targets, which inhibit growth-promoting signals from classic endocrine hormones (primarily estrogens for breast cancer and androgens for prostate cancer), are now called hormonal therapies. Other inhibitions of growth-signals, such as those associated with receptor tyrosine kinases, are targeted therapy.

Porphyria cutanea tarda (PCT) is a form of long-term porphyria characterised by fragile skin and sore blisters in areas of skin that receive higher levels of exposure to sunlight, such as the face and backs of the hands. These blisters burst easily resulting in erosions, crusts, and superficial ulcers. There is often associated darkened skin color and extra facial hair growth. Healing is typically slow, leading to scarring and milia, while changes such as hair loss, and alterations in nails may also occur. A slightly purplish tint may be seen around the eyes. Scleroderma-like thick skin may develop over fingers, scalp, behind the ears, at the back of the neck, or in the front of the chest. The urine may appear dark. Unlike other porphyrias, PCT does not cause severe illness.

The disorder results from a deficiency of uroporphyrinogen III decarboxylase, used in the production of heme, a vital component of hemoglobin. It is generally divided into three types; familial, non-familial, and acquired. The condition can be related to liver disease and a history of excessive alcohol consumption. It is a recognised complication of hepatitis C. Other associated conditions include type 2 diabetes, metabolic syndrome, HIV, SLE, and haemochromatosis. Smoking, and the use of estrogen in males with prostate cancer and females on combined contraceptive pill may also trigger PCT. Renal dialysis may cause retention of porphyrins and cause PCT.

Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and a variety of immune cells such as adipose tissue macrophages. Its main role is to store energy in the form of lipids, although it also cushions and insulates the body.

Previously treated as being hormonally inert, in recent years adipose tissue has been recognized as a major endocrine organ, as it produces hormones such as leptin, estrogen, resistin, and cytokines (especially TNFα). In obesity, adipose tissue is implicated in the chronic release of pro-inflammatory markers known as adipokines, which are responsible for the development of metabolic syndrome—a constellation of diseases including type 2 diabetes, cardiovascular disease and atherosclerosis.

The fight-or-flight or the fight-flight-freeze-or-fawn (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first described by Walter Bradford Cannon in 1914 to which he referred to as "the necessities of fighting or flight" in 1915. His theory states that animals react to threats with a general discharge of the sympathetic nervous system, preparing the animal for fighting or fleeing. More specifically, the adrenal medulla produces a hormonal cascade that results in the secretion of catecholamines, especially norepinephrine and epinephrine. The hormones estrogen, testosterone, and cortisol, as well as the neurotransmitters dopamine and serotonin, also affect how organisms react to stress. The hormone osteocalcin might also play a part.

This response is recognised as the first stage of the general adaptation syndrome that regulates stress responses among vertebrates and other organisms.

A hormone (from the Greek participle ὁρμῶν, "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physiology and behavior. Hormones are required for the normal development of animals, plants and fungi. Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein or peptides (e.g. insulin and CLE peptides), and gases (e.g. ethylene and nitric oxide).

Hormones are used to communicate between organs and tissues. In vertebrates, hormones are responsible for regulating a wide range of processes including both physiological processes and behavioral activities such as digestion, metabolism, respiration, sensory perception, sleep, excretion, lactation, stress induction, growth and development, movement, reproduction, and mood manipulation. In plants, hormones modulate almost all aspects of development, from germination to senescence.

The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems.

In humans, the major endocrine glands are the thyroid, parathyroid, pituitary, pineal, and adrenal glands, and the (male) testis and (female) ovaries. The hypothalamus, pancreas, and thymus also function as endocrine glands, among other functions. (The hypothalamus and pituitary glands are organs of the neuroendocrine system. One of the most important functions of the hypothalamus—it is located in the brain adjacent to the pituitary gland—is to link the endocrine system to the nervous system via the pituitary gland.) Other organs, such as the kidneys, also have roles within the endocrine system by secreting certain hormones. The study of the endocrine system and its disorders is known as endocrinology.The thyroid secretes thyroxine, the pituitary secretes growth hormone, the pineal secretes melatonin, the testis secretes testosterone, and the ovaries secrete estrogen and progesterone.

The breasts are two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryological tissues. The relative size and development of the breasts is a major secondary sex distinction between females and males. There is also considerable variation in size between individuals. Permanent breast growth during puberty is caused by estrogens in conjunction with the growth hormone. Female humans are the only mammals that permanently develop breasts at puberty; all other mammals develop their mammary tissue during the latter period of pregnancy.

In females, the breast serves as the mammary gland, which produces and secretes milk to feed infants. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple, and these tissues give the breast its distinct size and globular shape. At the ends of the ducts are lobules, or clusters of alveoli, where milk is produced and stored in response to hormonal signals. During pregnancy, the breast responds to a complex interaction of hormones, including estrogens, progesterone, and prolactin, that mediate the completion of its development, namely lobuloalveolar maturation, in preparation of lactation and breastfeeding.

Menopause is the time when menstrual periods permanently stop, marking the end of the reproductive stage for the female human. It typically occurs between the ages of 45 and 55, although the exact timing can vary. Menopause is usually a natural change related to a decrease in circulating blood estrogen levels. It can occur earlier in those who smoke tobacco. Other causes include surgery that removes both ovaries, some types of chemotherapy, or anything that leads to a decrease in hormone levels. At the physiological level, menopause happens because of a decrease in the ovaries' production of the hormones estrogen and progesterone. While typically not needed, measuring hormone levels in the blood or urine can confirm a diagnosis. Menopause is the opposite of menarche, the time when periods start.

In the years before menopause, a woman's periods typically become irregular, which means that periods may be longer or shorter in duration, or be lighter or heavier in the amount of flow. During this time, women often experience hot flashes; these typically last from 30 seconds to ten minutes and may be associated with shivering, night sweats, and reddening of the skin. Hot flashes can recur for four to five years. Other symptoms may include vaginal dryness, trouble sleeping, and mood changes. The severity of symptoms varies between women. Menopause is also known to cause thinning and drying of the skin as 30% of the skins collagen is lost during the first five years of menopause. Menopause before the age of 45 years is considered to be "early menopause", and ovarian failure or surgical removal of the ovaries before the age of 40 years is termed "premature ovarian insufficiency".

Progestogens, also sometimes written progestins, progestagens or gestagens, are a class of natural or synthetic steroid hormones that bind to and activate the progesterone receptors (PR). Progesterone is the major and most important progestogen in the body. The progestogens are named for their function in maintaining pregnancy (i.e., progestational), although they are also present at other phases of the estrous and menstrual cycles.

The progestogens are one of three types of sex hormones, the others being estrogens like estradiol and androgens/anabolic steroids like testosterone. In addition, they are one of the five major classes of steroid hormones, the others being the androgens, estrogens, glucocorticoids, and mineralocorticoids, as well as the neurosteroids. All endogenous progestogens are characterized by their basic 21-carbon skeleton, called a pregnane skeleton (C21). In similar manner, the estrogens possess an estrane skeleton (C18), and androgens, an androstane skeleton (C19).

Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible for the development of female secondary sexual characteristics such as the breasts, widening of the hips and a female pattern of fat distribution. It is also important in the development and maintenance of female reproductive tissues such as the mammary glands, uterus and vagina during puberty, adulthood and pregnancy. It also has important effects in many other tissues including bone, fat, skin, liver, and the brain.

The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive an embryo. These cycles are concurrent and coordinated, normally last between 21 and 35 days, with a median length of 28 days. Menarche (the onset of the first period) usually occurs around the age of 12 years; menstrual cycles continue for about 30–45 years.

Naturally occurring hormones drive the cycles; the cyclical rise and fall of the follicle stimulating hormone prompts the production and growth of oocytes (immature egg cells). The hormone estrogen stimulates the uterus lining (endometrium) to thicken to accommodate an embryo should fertilization occur. The blood supply of the thickened lining provides nutrients to a successfully implanted embryo. If implantation does not occur, the lining breaks down and blood is released. Triggered by falling progesterone levels, menstruation (commonly referred to as a "period") is the cyclical shedding of the lining, and is a sign that pregnancy has not occurred.