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Hormone (site na akụkụ Grik ὁρμῶν, "na-eme ka ọ na-agagharị") bụ klas nke mkpụrụ ndụ mgbaàmà na ọtụtụ mkpụrụ ndụ nke a na-eziga n'akụkụ ndị dị anya site na usoro dị mgbagwoju anya iji chịkwaa physiology na omume.[1] A chọrọ hormone maka mmepe ziri ezi nke anụmanụ, osisi na fungus. N'ihi nkọwa sara mbara nke hormone (dị ka molekụl na-enye mgbaàmà nke na-arụ ọrụ ya n'ebe dị anya site na ebe mmepụta ya), enwere ike ịhazi ọtụtụ ụdị molekụl dị ka homonụl. N'etiti ihe ndị a pụrụ iwere dị ka homonụ, bụ eicosanoids (dịka prostaglandins na thromboxanes), steroid (dịka oestrogen na brassinosteroid), amino acid derivatives (dịka epinephrine na auxin), protein ma ọ bụ peptides (dịka insulin na CLE peptides), na gas (dịka ethylene na nitric oxide).
A na-eji hormone eme ihe iji kwurịta okwu n'etiti akụkụ ahụ na anụ ahụ. N'ime anụ ndị nwere azụ, homonụ na-ahụ maka ịchịkwa usoro dịgasị iche iche nke ahụike na omume omume dịka ịgbari nri, metabolism, iku ume, nghọta mmetụta, ụra, nsị, inye nwa ara, nrụgide, uto na mmepe, mmegharị, ọmụmụ, na njikwa ọnọdụ.[2][3][4] N'ime osisi, homonụ na-agbanwe ihe fọrọ nke nta ka ọ bụrụ akụkụ niile nke mmepe, site na ntolite ruo na ịka nká.[5]
Mmiri ogwu ahu na-emetụta mkpụrụ ndụ ndị dị anya site na ijikọta na protein ndị na-anabata ihe na mkpụrụ ndụ a na-achọ, na-akpata mgbanwe na ọrụ mkpụrụ ndụ. Mgbe hormone na-ejikọta na onye na-anabata ya, ọ na-eme ka ụzọ mgbaàmà nke na-emekarị ka transcription nke mkpụrụ ndụ ihe nketa rụọ ọrụ, na-akpata mmụba nke protein ndị a na-achọ. Hormones nwekwara ike ịrụ ọrụ na ụzọ ndị na-abụghị nke genomic nke na-ejikọta na mmetụta nke genomic.[6] Mmiri homonụ na-agbaze (dị ka peptide na amines) na-arụkarị ọrụ n'elu mkpụrụ ndụ ndị a na-achọ site na ndị ozi nke abụọ. Hormone ndị na-agbaze abụba, (dị ka steroid) na-agafe n'ime plasma membranes nke mkpụrụ ndụ ndị a na-achọ (ma cytoplasmic ma nuclear) iji rụọ ọrụ n'ime nucleus ha. Brassinosteroids, ụdị polyhydroxysteroids, bụ klas nke isii nke homonụ osisi ma nwee ike ịba uru dị ka ọgwụ na-alụso ọrịa kansa ọgụ maka akpụ na-emeghachi omume endocrine iji kpatara apoptosis ma belata uto osisi. N'agbanyeghị na ha na-agbaze abụba, ha ka na-ejikọta na onye na-anabata ha n'elu mkpụrụ ndụ.[7]
Na vertibrate, akpa endocrine ha mara anya nke oma banyere any aru nke hormones nzuzo na ime. Hormone secretion occurs in response to specific biochemical signals and is often subject to negative feedback regulation. For instance, high blood sugar (serum glucose concentration) promotes insulin synthesis. Insulin then acts to reduce glucose levels and maintain homeostasis, leading to reduced insulin levels. Upon secretion, water-soluble hormones are readily transported through the circulatory system. Lipid-soluble hormones must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form ligand-protein complexes. Some hormones, such as insulin and growth hormones, can be released into the bloodstream already fully active. Other hormones, called prohormones, must be activated in certain cells through a series of steps that are usually tightly controlled.[8] The endocrine system secretes hormones directly into the bloodstream, typically via fenestrated capillaries, whereas the exocrine system secretes its hormones indirectly using ducts. Hormones with paracrine function diffuse through the interstitial spaces to nearby target tissue.
Osisi enweghị akụkụ pụrụ iche maka mmepụta nke homonụ, ọ bụ ezie na enwere nkesa nke mmepụta homonụ. Dịka ọmụmaatụ, a na-emepụta hormone auxin karịsịa na isi akwụkwọ ndị na-eto eto na n'ime osisi apical meristem. Enweghị gland ndị pụrụ iche pụtara na isi ebe mmepụta hormone nwere ike ịgbanwe n'oge ndụ nke osisi, ebe mmepụta na-adabere na afọ na gburugburu ebe obibi nke osisi ahụ.[9]
Ihe mgbaàmà hormone na-agụnye usoro ndị a:[10]
A na-ahụ mkpụrụ ndụ na-emepụta hormone na gland endocrine, dị ka gland thyroid, ovaries, na testicles.[11] A na-eji exocytosis na ụzọ ndị ọzọ nke mbugharị membrane eme ihe iji wepụta homonụ mgbe a na-egosi gland endocrine. Ihe nlereanya nke hierarchical bụ mmelite nke usoro mgbaàmà homonụ. Ndị na-anata mkpụrụ ndụ nke otu mgbaàmà homonụ nwere ike ịbụ otu n'ime ọtụtụ ụdị mkpụrụ ndụ na-ebi n'ime ọnụ ọgụgụ dị iche iche nke anụ ahụ, dịka ọ dị maka insulin, nke na-akpata mmetụta dịgasị iche iche nke usoro ahụike. Ụdị anụ ahụ dị iche iche nwekwara ike imeghachi omume n'ụzọ dị iche na otu mgbaàmà homonụ. [citation needed]
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