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Inhibin B
Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. Identified in 1986, activin enhances FSH biosynthesis and secretion, and participates in the regulation of the menstrual cycle. Many other functions have been found to be exerted by activin, including roles in cell proliferation, differentiation, apoptosis, metabolism, homeostasis, immune response, wound repair, and endocrine function. Conversely, inhibin downregulates FSH synthesis and inhibits FSH secretion. The existence of inhibin was hypothesized as early as 1916; however, it was not demonstrated to exist until Neena Schwartz and Cornelia Channing's work in the mid-1970s, after which both proteins were molecularly characterized ten years later. Activin is a dimer composed of two identical or very similar beta subunits. Inhibin is also a dimer wherein the first component is a beta subunit similar or identical to the beta subunit in activin. However, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a Stabilizer (chemistry), stabilizer in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocrine System
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 Organ (biology), organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland, thyroid, parathyroid gland, parathyroid, pituitary gland, pituitary, pineal gland, 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 Neuroendocrinology#Neuroendocrine system, neuroendocrine system. One of the most important functions of the hypothalamusit is located in the brain adjacent to the pituitary glandis to link the endocrine system to the nervous system via the pituitary gland.) Other organs, such as the kidneys, also have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pituitary Gland
The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the human brain, brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus control much of the body's endocrine system. It is seated in part of the sella turcica a fossa (anatomy), depression in the sphenoid bone, known as the hypophyseal fossa. The human pituitary gland is ovoid, oval shaped, about 1 cm in diameter, in weight on average, and about the size of a kidney bean. Digital version. There are two main lobes of the pituitary, an anterior pituitary, anterior lobe, and a posterior pituitary, posterior lobe joined and separated by a small intermediate lobe. The anterior lobe (adenohypophysis) is the glandular part that produces and secretes several hormones. The posterior lobe (neurohypophysis) secretes neurohypophysial hormones produced in the hypothalamus. Both lobes have different origins and they are both co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonad
A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of Spermatozoon, spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals (and some humanssee Ovotesticular syndrome) have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone (LH) and follicle-stimulating hormone (FSH), produced and secreted by gonadotropic cell, gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone (GnRH) produced in the hypothalamus. Development The gonads develop f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Clawed Frog
The African clawed frog (''Xenopus laevis''), also known as simply xenopus, African clawed toad, African claw-toed frog or the ''platanna'') is a species of African Aquatic animal, aquatic frog of the family Pipidae. Its name is derived from the short black claws on its feet. The word ''Xenopus'' means 'strange foot' and ''laevis'' means 'smooth'. The species is found throughout much of Sub-Saharan Africa (Nigeria and Sudan to South Africa), and in isolated, Introduced species, introduced populations in North America, South America, Europe, and Asia. All species of the family Pipidae are tongueless, toothless and completely aquatic. They use their hands to shove food in their mouths and down their throats and a hyobranchial pump to draw or suck things in their mouth. Pipidae have powerful legs for swimming and lunging after food. They also use the claws on their feet to tear pieces of large food. They have no external eardrums, but instead subcutaneous cartilaginous disks that se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common descent, common ancestor after having been subjected to adaptation (biology), adaptive modifications for different purposes as the result of natural selection. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this from Aristotle's biology onwards, and it was explicitly analysed by Pierre Belon in 1555. A common example of homologous structures is the forelimbs of vertebrates, where the bat wing development, wings of bats and origin of avian flight, birds, the arms of primates, the front flipper (anatomy), flippers of whales, and the forelegs of quadrupedalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activin Inhibin
Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. Identified in 1986, activin enhances FSH biosynthesis and secretion, and participates in the regulation of the menstrual cycle. Many other functions have been found to be exerted by activin, including roles in cell proliferation, differentiation, apoptosis, metabolism, homeostasis, immune response, wound repair, and endocrine function. Conversely, inhibin downregulates FSH synthesis and inhibits FSH secretion. The existence of inhibin was hypothesized as early as 1916; however, it was not demonstrated to exist until Neena Schwartz and Cornelia Channing's work in the mid-1970s, after which both proteins were molecularly characterized ten years later. Activin is a dimer composed of two identical or very similar beta subunits. Inhibin is also a dimer wherein the first component is a beta subunit similar or identical to the beta subunit in activin. However, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfide Bond
In chemistry, a disulfide (or disulphide in British English) is a compound containing a functional group or the anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups. In inorganic chemistry, the anion appears in a few rare minerals, but the functional group has tremendous importance in biochemistry. Disulfide bridges formed between thiol groups in two cysteine residues are an important component of the tertiary and quaternary structure of proteins. Compounds of the form are usually called '' persulfides'' instead. Organic disulfides Structure Disulfides have a C–S–S–C dihedral angle approaching 90°. The S–S bond length is 2.03 Å in diphenyl disulfide, similar to that in elemental sulfur. Disulfides are usually symmetric but they can also be unsymmetric. Symmetrical disulfides are compounds of the formula . Most disulfides encountered in organosulfur chemistry are symmetrical disulfides. Unsy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transforming Growth Factor Beta Superfamily
The transforming growth factor beta (TGF-β) superfamily is a large group of structurally related cell regulatory proteins that was named after its first member, TGF-β1, originally described in 1983. They interact with TGF-beta receptors. Many proteins have since been described as members of the TGF-β superfamily in a variety of species, including invertebrates as well as vertebrates and categorized into 23 distinct gene types that fall into four major subfamilies: * The TGF-β subfamily * The bone morphogenetic proteins and the growth differentiation factors * The activin and inhibin subfamilies * The left-right determination factors * A group encompassing various divergent members Transforming growth factor-beta (TGF-beta) is a multifunctional peptide that controls proliferation, differentiation and other functions in many cell types. TGF-beta-1 is a peptide of 112 amino acid residues derived by proteolytic cleavage from the C-terminal of a precursor protein. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Differentiation Factor
Growth differentiation factors (GDFs) are a subfamily of proteins belonging to the transforming growth factor beta superfamily that have functions predominantly in development. Types Several members of this subfamily have been described, and named GDF1 through GDF15. * GDF1 is expressed chiefly in the nervous system and functions in left-right patterning and mesoderm induction during embryonic development. * GDF2 (also known as BMP9) induces and maintains the response embryonic basal forebrain cholinergic neurons (BFCN) have to a neurotransmitter called acetylcholine, and regulates iron metabolism by increasing levels of a protein called hepcidin. * GDF3 is also known as "Vg-related gene 2" (Vgr-2). Expression of GDF3 occurs in ossifying bone during embryonic development and in the thymus, spleen, bone marrow brain, and adipose tissue of adults. It has a dual nature of function; it both inhibits and induces early stages of development in embryos. *GDF5 is expressed in the develo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Morphogenetic Protein
Bone morphogenetic proteins (BMPs) are a group of growth factors also known as cytokines and as metabologens. Professor Marshall Urist and Professor Hari Reddi discovered their ability to induce the formation of bone and cartilage, BMPs are now considered to constitute a group of pivotal morphogenetic signals, orchestrating tissue architecture throughout the body. The important functioning of BMP signals in physiology is emphasized by the multitude of roles for dysregulated BMP signalling in pathological processes. Cancerous disease often involves misregulation of the BMP signalling system. Absence of BMP signalling is, for instance, an important factor in the progression of colon cancer, and conversely, overactivation of BMP signalling following reflux-induced esophagitis provokes Barrett's esophagus and is thus instrumental in the development of esophageal adenocarcinoma. Recombinant human BMPs (rhBMPs) are used in orthopedic applications such as spinal fusions, nonunions, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-Müllerian Hormone
Anti-Müllerian hormone (AMH), also known as Müllerian-inhibiting hormone (MIH), is a glycoprotein hormone structurally related to Activin and inhibin, inhibin and activin from the transforming growth factor beta superfamily, whose key roles are in growth differentiation and folliculogenesis. In humans, it is encoded by the gene, on chromosome 19p13.3, while its Receptor (biochemistry), receptor is encoded by the gene on chromosome 12. AMH is activated by SOX9 in the Sertoli cells of the male fetus. Its expression inhibits the development of the female reproductive tract, or Müllerian ducts (paramesonephric ducts), in the male embryo, thereby arresting the development of fallopian tubes, uterus, and upper vagina. ''AMH'' expression is critical to sex differentiation at a specific time during fetal development, and appears to be tightly regulated by nuclear receptor Steroidogenic factor 1, SF-1, GATA transcription factor, transcription GATA factors, sex-reversal gene DAX1, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
