Raws li ib qho tseem ceeb ntawm tib neeg lub cev,cov roj cholesterolrmuaj nyob rau hauv cov zaub mov ntuj thiab tuaj yeem tsim los yog hloov los ntawm peb lub peev xwm. Cov hauv qab no yog cov lus qhia ntxaws txog zaub mov thiab lub cev nws tus kheej.
Txawm hais tias nws muaj nyob rau hauv cov khoom noj tsiaj, nws cov ntsiab lus sib txawv heev hauv cov tsiaj sib txawv thiab cov tsiaj sib txawv. Feem ntau hais lus, cov ntsiab lus ntawm cov tsiaj nyeg yog siab dua cov nqaij qaib nqaij, nqaij nyuj rog yog siab dua li cov nqaij ntshiv, plhaub thiab mollusks siab tshaj cov ntses zoo tib yam, thaum cov ntsiab lus ntawm qe qe, roe thiab tsiaj viscera yog siab tshaj. .
Tib neeg cov ntaub so ntswg muaj qhov tseem ceeb ntawm ntau cov biofilms tshwj tsis yog rau cov mitochondrial membrane thiab endoplasmic reticulum membrane. Nws yog qhov tseem ceeb sterol hauv lub cev. Nws tsis yog tsuas yog ib qho tseem ceeb ntawm cov cell membrane tab sis kuj yog ib qho precursor ntawm steroid hormones, vitamin D thiab bile acids. Tib neeg lub cev muaj 2G ntawm nws ib kilogram ntawm lub cev hnyav, thiab tag nrho cov ntsiab lus ntawm 70kg yog hais txog 140g. Raws li thaum ntxov xyoo pua 18th, nws tau pom nyob rau hauv gallstones. Nyob rau hauv 1816, tus kws tshuaj bencher hu ua cov tshuaj no nrog lipid zog. dav muaj nyob rau hauv cov tsiaj, tshwj xeeb tshaj yog nyob rau hauv lub hlwb thiab paj hlwb. Nws tseem yog siab nyob rau hauv lub raum, spleen, tawv nqaij, siab thiab bile.it yog ib qho tseem ceeb thiab tseem ceeb tshuaj nyob rau hauv cov tsiaj cov ntaub so ntswg thiab hlwb. Nws koom nrog hauv kev tsim cov cell membrane thiab cov khoom siv raw rau kev sib txuas ntawm cov kua tsib acids, vitamin D, thiab steroids. Nws kuj tseem tuaj yeem hloov mus rau hauv cov kua tsib acids, cov tshuaj steroid thiab 7-dehydrocholesterol tom qab metabolism, thiab 7-dehydrocholesterol yuav hloov mus rau hauv vitamin D3 tom qab ultraviolet irradiation, yog li nws tsis yog ib yam khoom ua rau tib neeg lub cev.
Kev tsim cov roj (cholesterol) hauv tib neeg lub cev:
1. Forming formyl 3-hydroxy-3-menthyl glutarate yog thawj txheej txheem ntawm nws synthesis hauv tib neeg lub cev. Cov txheej txheem no tau ua tiav hauv cov kua cell ntawm tib neeg lub cev. Peb cov molecules ntawm acetyl CoA yog catalyzed los ntawm thiolase thiab HMG-CoA synthase kom ua tiav cov txheej txheem no. Cov txheej txheem no zoo ib yam li kev tsim cov txheej txheem ntawm ketones hauv tib neeg lub cev, uas txawv ntawm sab hauv ntawm tes. Cov txheej txheem no ua tiav hauv cov kua cell; Kev tsim ntawm ketone lub cev yog ua nyob rau hauv mitochondria ntawm tib neeg hepatocytes.
2. Kev tsim cov mevalonate yog qhov tseem ceeb thib ob ntawm kev tsim cov roj cholesterol. Cov kauj ruam no tuaj yeem ua tiav tsuas yog nrog cov catalysis ntawm HMG CoA reductase, thiab tag nrho cov tshuaj tiv thaiv txheej txheem ntawm kev tsim mevalonate yog irreversible. Hauv cov txheej txheem no, HMG reductase tshwm sim raws li tus nqi txwv enzyme ntawm cov roj cholesterol synthesis.
3. Cov txheej txheem kawg yog qhov tsim ntawmcholesterol hmoov. Cov txheej txheem no yuav tsum muaj cov kauj ruam thib ob. Cov tsim mevalonic acid mus los ntawm ntau cov tshuaj tiv thaiv, xws li phosphorylation, decarboxylation, dehydroxylation, thiab lwm yam, feem ntau ntawm tag nrho cov, tom qab ib tug series ntawm redox cov tshuaj tiv thaiv, nws thiaj li yuav synthesize 27c cholesterol, uas yog feem ntau hu ua cholesterol nyob rau hauv lub cev. .