【正文】 marginal deficiency: influence health without symptoms 一、 Vit A retinal (A1) sdehydroretinal (A2) retinol βcarotene 1. structures and properties: structure 15 10 1214CH 3 CH 3CH 3CH 3CH 3CH 2 OHA1 15 10 1214CH 3 CH 3CH 3CH 3CH 3CH 2 OHA2 (biopotency of A2 is 40% that of A1) C 14CH 2 OHRCH 3HC C14RCH 3HCCH 2 OHTrans configuration Cis configuration CH 3 CH 3 CH 3CH 3CH 3CH 3CH 3CH 3CH 3CH 3151539。CH3CH3CH3RCH3CH3CH3Rβcarotene (provitamin A) αcarotene γcarotene solubility: soluble in fats and all the usual anic solvents, insoluble in water. Oxidation: be oxidized by light,air and oxidant such as MnO2 (Manganese dioxide). Isomerization(異構(gòu)化 )： retinol is isomerized by light Stability: sensitive toward acids but stable to base. Color reaction: retinal and its esters have a yellowish green fluorescence(熒光 )。 Acid reagents give blue color or purple(sulfuric acid) reaction with Vit. A Properties of 2. Metabolism (1)absorption: βcarotene retinal small intestine (水解 ) 1/3(fat,bile acid) retinyl ester upper intestine retinol mucosal cell wall Esterified chylomicron mucosal cell (水解 ) （還原） 189。 from βcarotene mucosal cell (2) Transport and storage retinyl esters lymphatic system blood scream storage liver(90%) Kidney Lung ,eye free retinal blood scream Tissue for metabolic requirement 水解 chylomicron ? The blood level of is independent of the liver reserve. ? Retinol is transported in plasma in association with a specific transport ? Protein RBP: level in plasm is proportional to the level of RBP. (3). Excretion In liver Glucaronides(葡萄糖苷酸 ) blie Reabsorbed Excreted with feces liver In tissues Methylated metabolites urine 3. Function (1) in vision: Gee Wald was awarded the Nobel Prize for medicine in 1967 for his discovery of the role of VitA in the visual system. Retinal 11cis form +protein +ospin Iodopsin(藍(lán) ) Rhodopsin（紅） High light Dim light Alltrans retinal +protein Producing a nervous exitation brain Visual sensations Some of all transretinal Dark adaptation (2) Effect on cell membrance:regulating membrance structure and function by influencing the biosynthesis of glycoprotein because VitA is headed for carrying mono or oligosacchride units to acceptor site。 RAR9all cisretinoic acid, RXR9all trans (or all cis)retinoic acid gene expression. (3) Influencing the synthesis of bone and both serum and muscle influence the growth, development and reproduction. (4) Against cancer (βcarotene is more important) and regulating immunity 4. Deficiency (1) night blindness and xerosis (干燥癥 ) xerosis of cornea(角膜 ) corneal distortion (變形 ) blindness (2) xerosis occurs throughout the body infection and pathologic calcification（鈣化作用） lesions。 epithelia cell horng(角化 )； nerve lesion。 deformities (畸形 ) in the fetus. (3) influencing the growth and development (especially bone,teeth) (4) others : Hb and immunity decrease Early stage Late stage Vitamin A deficiency is a world wide problem that leads to eye diseases, severe infection and death in many people. Most of the affected live in lowine countries. It is estimated that about 750 million people are affected by vitamin A deficiency globally. Vulnerable groups are: Children from six months to six years. Pregnant women. Lactating women. 5. Toxicity (1) Infants: transient hydrocephalus(暫時(shí)腦積水 ) and vomiting. (2) Adult (chromic): 2030 times of RDA. Fatigue(疲勞 ),malaise(不適 ),lethargy(嗜睡癥 ), abdominal disfort,bone or joint pain or both, headache,insomnia(失眠 ), night sweats,loss of body hair or brittle nails or both,指甲脆性， dry, scaly(鱗狀 ), rough skin . (3) Osteoclasts (破骨細(xì)胞 ) activities increasing. (4) Others: fetus deformities, yellow skin, …… 6. Estimation of nutritional level of VitA (1) VitA level in plasma: ~(10~20ug/dL) – deficiency. But normal level(30ug/dL)does not mean that VitA is enough. (2) 改進(jìn)的相對(duì)計(jì)量反應(yīng)試驗(yàn)， MRDR 脫氫視黃醇 /視黃醇 ,， 缺乏 (3) RBP in plasma . (4) Dark adaptation (5) 眼結(jié)膜印跡細(xì)胞學(xué)法 ， CIC conjunctive impression cytology. (6) Symptoms of eye 7. DRIs and food source 1IU VitA= RE 1μg Retinol= RE 1μg βcarotene= 1μg other carotene= μg RE (2) DRIs: ?Adults: 800μg RE/d ?Pregnancy: 1000μg RE/d ?Wet nurse: 1200μg RE/d (1) Units β carotene: in plant Vit. A: animal food 二、 Vit D (shortened) 1. Structure HOCH2HOHO73CH2HO Ultraviolet light Ultraviolet light (1) Regulating plasma Ca and P with the parathyroid hormone plasma Ca Ca, P absorption renal reabsorption Ca from bone plasma Ca, P (2) Facilitating(促進(jìn) ) mineralization of the bone (3) Preventing ricket, osteomalacia (軟骨病 ) and osteoporosis(骨質(zhì)疏松癥 ). 2. Function 佝僂?。?O形畸形 3. DRIs and dietary source (1) DRIs ? Adult: 5μ g/d (200IU/d) ? Others:10μ g/d(400IU/d) (2) Food source: Same as VitA and sun light. 三、 (tocopherol, 生育酚 ) 1. Function and deficiency (1) reproductive system: ?male: degeneration of seminiferous (生精 ) epithelium ?female: impairing vascular of fetal and placenta asphyxia (窒息 ) and death of fetus. ?man: No evidence to relate ma