Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy.
A secondary sex characteristic is a physical characteristic of an organism that is related to or derived from its sex, but not directly part of its reproductive system. In humans, these characteristics typically start to appear during puberty. In animals, they can start to appear at sexual maturity. In humans, secondary sex characteristics include enlarged breasts and widened hips of females, facial hair and Adam's apples on males, and pubic hair on both. In non-human animals, secondary sex characteristics include, for example, the manes of male lions, the bright facial and rump coloration of male mandrills, and horns in many goats and antelopes.
Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the major progestogen in the body. Progesterone has a variety of important functions in the body. It is also a crucial metabolic intermediate in the production of other endogenous steroids, including the sex hormones and the corticosteroids, and plays an important role in brain function as a neurosteroid.
The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal physiology during pregnancy. The placenta connects to the fetus via the umbilical cord, and on the opposite aspect to the maternal uterus in a species-dependent manner. In humans, a thin layer of maternal decidual (endometrial) tissue comes away with the placenta when it is expelled from the uterus following birth. Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development.
Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development that is influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood.
Estrone (E1), also spelled oestrone, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estriol. Estrone, as well as the other estrogens, are synthesized from cholesterol and secreted mainly from the gonads, though they can also be formed from adrenal androgens in adipose tissue. Relative to estradiol, both estrone and estriol have far weaker activity as estrogens. Estrone can be converted into estradiol, and serves mainly as a precursor or metabolic intermediate of estradiol. It is both a precursor and metabolite of estradiol.
Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens.
Placentophagy, also known as placentophagia, is the act of consuming part or all of the afterbirth following parturition in mammals. Parturition involves the delivery of the neonate, as well as the placenta and fetal membranes. The placenta is a critical organ that develops in the maternal uterus during pregnancy to support the fetus. It connects to the fetus via the umbilical cord in order to allow nutrient transport, waste excretion and gas exchange between mother and fetus. The morphological features of the placenta differ among species, but the function is universal. The behaviour is characteristic to the mother of the majority of placental mammals. Significant documentation has been provided on placentophagy in a range of animals.
Bioidentical hormone replacement therapy (BHRT), also known as bioidentical hormone therapy(BHT) or natural hormone therapy, is the use of hormones that are identical on a molecular level with endogenous hormones in hormone replacement therapy. It may also be combined with blood and saliva testing of hormone levels, and the use of pharmacy compounding to obtain hormones in an effort to reach a targeted level of hormones in the body. A number of claims by some proponents of BHT have not been confirmed through scientific testing. Specific hormones used in BHT include estrone, estradiol, progesterone, testosterone, dehydroepiandrosterone (DHEA), and estriol.
Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exogenously. They may also be used for chemoprevention in women at high risk for breast cancer.
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
An estrogen patch, or oestrogen patch, is a transdermal delivery system for estrogens such as estradiol and ethinylestradiol which can be used in menopausal hormone therapy, feminizing hormone therapy for transgender women, hormonal birth control, and other uses. Transdermal preparations of estrogen are metabolized differently than oral preparations. Transdermal estrogens avoid the first pass through the liver and thus potentially reduce the risk of blood clotting and stroke.
Aromatase deficiency is a rare condition characterized by extremely low levels or complete absence of the enzyme aromatase activity in the body. It is an autosomal recessive disease resulting from various mutations of gene CYP19 (P450arom) which can lead to ambiguous genitalia and delayed puberty in females, continued linear growth into adulthood and osteoporosis in males and virilization in pregnant mothers. As of 2020, fewer than 15 cases have been identified in genetically male individuals and at least 30 cases in genetically female individuals.
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a female, the testes in a male. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Before puberty, the external sex organs, known as primary sexual characteristics, are sex characteristics that distinguish males and females. Puberty leads to sexual dimorphism through the development of the secondary sex characteristics, which further distinguish the sexes.
Xenohormones or environmental hormones produced outside of the human body which exhibit endocrine hormone-like properties. They may be either of natural origin, such as phytoestrogens, which are derived from plants, or of synthetic origin. These compounds are able to activate the same endocrine receptors as their natural counterparts and are thus frequently implicated in endocrine disruption. The most commonly occurring xenohormones are xenoestrogens, which mimic the effects of estrogen. Other xenohormones include xenoandrogens and xenoprogesterones. Xenohormones are used for a variety of purposes including contraceptive & hormonal therapies, and agriculture. However, exposure to certain xenohormones early in childhood development can lead to a host of developmental issues including infertility, thyroid complications, and early onset of puberty. Exposure to others later in life has been linked to increased risks of testicular, prostate, ovarian, and uterine cancers.
Human placentophagy, or consumption of the placenta, is defined as "the ingestion of a human placenta postpartum, at any time, by any person, either in raw or altered form". While there are several anecdotes of different cultures practicing placentophagy in varying contexts, maternal placentophagy started in the US in the 1970s, with little to no evidence of its practice in any traditional or historic culture. Midwives and alternative-health advocates in the U.S. are the primary groups encouraging post-partum maternal placentophagy.
Gynecomastia is the abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Gynecomastia can cause significant psychological distress or unease.
Li Shizhen's (1597) Bencao gangmu, the classic materia medica of traditional Chinese medicine (TCM), included 35 human drugs, including organs, bodily fluids, and excreta. Crude drugs derived from the human body were commonplace in the early history of medicine. Some of these TCM human drug usages are familiar from alternative medicine, such as medicinal breast milk and urine therapy. Others are uncommon, such as the "mellified man", which was a foreign nostrum allegedly prepared from the mummy of a holy man who only ate honey during his last days and whose corpse had been immersed in honey for 100 years.
Estrogenic substances, also referred to as natural estrogens and sold under the brand name Amniotin among others, is an estrogen medication which was marketed in the 1930s and 1940s and is no longer available. It was a purified extract of animal material such as horse urine, placenta, and/or amniotic fluid, and contained a non-crystalline mixture of estrogens, including estrone, 17β-estradiol, 17α-estradiol, and/or equilin. The medication was thought to contain estrone as its major active ingredient and was described as an estrone-like preparation, or as "essentially estrone". Estrogenic substances was originally produced from the urine of pregnant women, placenta, and/or amniotic fluid, but by the early 1940s, it was manufactured exclusively from the urine of stallions or pregnant mares, similarly to almost all other estrogen preparations on the market.
Animal products in pharmaceuticals play a role as both active and inactive ingredients, the latter including binders, carriers, stabilizers, fillers, and colorants. Animals and their products may also be used in pharmaceutical production without being included in the product itself.
