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.
The hypothalamus is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is the size of an almond.
Leptin is a hormone predominantly made by adipose cells and its primary role is likely to regulate long-term energy balance.
Orexin, also known as hypocretin, is a neuropeptide that regulates arousal, wakefulness, and appetite. The most common form of narcolepsy, type 1, in which the individual experiences brief losses of muscle tone, is caused by a lack of orexin in the brain due to destruction of the cells that produce it. It exists in the forms of Orexin-A and Orexin-B.
Wakefulness is a daily recurring brain state and state of consciousness in which an individual is conscious and engages in coherent cognitive and behavioral responses to the external world.
The arcuate nucleus of the hypothalamus is an aggregation of neurons in the mediobasal hypothalamus, adjacent to the third ventricle and the median eminence. The arcuate nucleus includes several important and diverse populations of neurons that help mediate different neuroendocrine and physiological functions, including neuroendocrine neurons, centrally projecting neurons, and astrocytes. The populations of neurons found in the arcuate nucleus are based on the hormones they secrete or interact with and are responsible for hypothalamic function, such as regulating hormones released from the pituitary gland or secreting their own hormones. Neurons in this region are also responsible for integrating information and providing inputs to other nuclei in the hypothalamus or inputs to areas outside this region of the brain. These neurons, generated from the ventral part of the periventricular epithelium during embryonic development, locate dorsally in the hypothalamus, becoming part of the ventromedial hypothalamic region. The function of the arcuate nucleus relies on its diversity of neurons, but its central role is involved in homeostasis. The arcuate nucleus provides many physiological roles involved in feeding, metabolism, fertility, and cardiovascular regulation.
Linda Brown Buck is an American biologist best known for her work on the olfactory system. She was awarded the 2004 Nobel Prize in Physiology or Medicine, along with Richard Axel, for their work on olfactory receptors. She is currently on the faculty of the Fred Hutchinson Cancer Research Center in Seattle.
Steroid hormone receptors are found in the nucleus, cytosol, and also on the plasma membrane of target cells. They are generally intracellular receptors and initiate signal transduction for steroid hormones which lead to changes in gene expression over a time period of hours to days. The best studied steroid hormone receptors are members of the nuclear receptor subfamily 3 (NR3) that include receptors for estrogen and 3-ketosteroids. In addition to nuclear receptors, several G protein-coupled receptors and ion channels act as cell surface receptors for certain steroid hormones.
Endocrine glands are ductless glands of the endocrine system that secrete their products, hormones, directly into the blood. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands. The hypothalamus and pituitary glands are neuroendocrine organs.
Estrogen receptors (ERs) are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen (17β-estradiol). Two classes of ER exist: nuclear estrogen receptors, which are members of the nuclear receptor family of intracellular receptors, and membrane estrogen receptors (mERs), which are mostly G protein-coupled receptors. This article refers to the former (ER).
Agouti-related protein (AgRP), also called agouti-related peptide, is a neuropeptide produced in the brain by the AgRP/NPY neuron. It is synthesized in neuropeptide Y (NPY)-containing cell bodies located in the ventromedial part of the arcuate nucleus in the hypothalamus. AgRP is co-expressed with NPY and acts to increase appetite and decrease metabolism and energy expenditure. It is one of the most potent and long-lasting of appetite stimulators. In humans, the agouti-related peptide is encoded by the AGRP gene.
The ventromedial nucleus of the hypothalamus is a nucleus of the hypothalamus. "The ventromedial hypothalamus (VMH) is a distinct morphological nucleus involved in terminating hunger, fear, thermoregulation, and sexual activity." This nuclear region is involved in the recognition of the feeling of fullness.
Estrogen receptor alpha (ERα), also known as NR3A1, is one of two main types of estrogen receptor, a nuclear receptor that is activated by the sex hormone estrogen. In humans, ERα is encoded by the gene ESR1.
G protein-coupled estrogen receptor 1 (GPER), also known as G protein-coupled receptor 30 (GPR30), is a protein that in humans is encoded by the GPER gene. GPER binds to and is activated by the female sex hormone estradiol and is responsible for some of the rapid effects that estradiol has on cells.
Estrogen receptor beta (ERβ) also known as NR3A2 is one of two main types of estrogen receptor—a nuclear receptor which is activated by the sex hormone estrogen. In humans ERβ is encoded by the ESR2 gene.
Estrogen-related receptor alpha (ERRα), also known as NR3B1, is a nuclear receptor that in humans is encoded by the ESRRA gene. ERRα was originally cloned by DNA sequence homology to the estrogen receptor alpha, but subsequent ligand binding and reporter-gene transfection experiments demonstrated that estrogens did not regulate ERRα. Currently, ERRα is considered an orphan nuclear receptor.
Catherine Dulac is a French-American biologist. She is the Higgins Professor in Molecular and Cellular Biology at Harvard University, where she served as department chair from 2007 to 2013. She is also an investigator at the Howard Hughes Medical Institute. She was born in 1963 in France. She came to the United States for her postdoctoral study in 1991.
Neurodegenerative diseases can disrupt the normal human homeostasis and result in abnormal estrogen levels. For example, neurodegenerative diseases can cause different physiological effects in males and females. In particular, estrogen studies have revealed complex interactions with neurodegenerative diseases. Estrogen was initially proposed to be a possible treatment for certain types of neurodegenerative diseases but a plethora of harmful side effects such as increased susceptibility to breast cancer and coronary heart disease overshadowed any beneficial outcomes. On the other hand, Estrogen Replacement Therapy has shown some positive effects with postmenopausal women. Estrogen and estrogen-like molecules form a large family of potentially beneficial alternatives that can have dramatic effects on human homeostasis and disease. Subsequently, large-scale efforts were initiated to screen for useful estrogen family molecules. Furthermore, scientists discovered new ways to synthesize estrogen-like compounds that can avoid many side effects.
A bone growth factor is a growth factor that stimulates the growth of bone tissue.
Kisspeptin, neurokinin B, and dynorphin (KNDy) neurons are neurons in the hypothalamus of the brain that are central to the hormonal control of reproduction.
