non-alcoholic liver disorders

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1 Gut, 1986, 27, Liver nd biliry Impired cetldehyde metbolism in ptients with non-lcoholic liver disorders K MTTHEWSON, H L MRDINI, K BRTLETT, ND C RECORD From the Gstroenterology Unit nd Deprtment of Clinicl Biochemistry nd Metbolic Medicine, Royl Victori Infirmry nd University ofnewcstle Upon Tyne SUMMRY In order to determine the specificity of bnormlities of lcohol metbolism in ptients with lcoholic liver disese, blood cetldehyde concentrtions fter orl ethnol chllenge nd the ctivities of lcohol metbolising enzymes in liver biopsy smples hve been determined in ptients with lcoholic liver disese nd wide vriety of non-lcoholic liver disorders. Significnt decreses in heptic cytosolic ldehyde dehydrogense ctivity were ssocited with significnt increses in cetldehyde concentrtions fter ethnol in both ptient groups compred with control subjects. There ws significnt correltion between heptic cytosolic ldehyde dehydrogense nd men blood cetldehyde concentrtion 3-18 min fter ethnol ingestion (y= x; r= - 56; p<-1) confirming the importnce of this enzyme in controlling blood cetldehyde concentrtions. These findings suggest tht disturbnces in lcohol metbolism in ptients with lcoholic liver disese re the consequence of liver dmge rther thn specific bnormlity predisposing to lcohol induced liver injury. cetldehyde, the first product of ethnol metbolism is highly toxic substnce 1-4 nd not surprisingly is considered possible meditor of lcoholic liver dmge. lthough the ssy of cetldehyde in biologicl fluids is difficult nd erlier techniques hve been criticised,j8 there re now severl reports of rised blood cetldehyde concentrtions in lcoholics fter both intrvenous9 1 nd orl" dministrtion of ethnol. Such rises could be explined by either incresed ethnol or decresed cetldehyde oxidtion. cetldehyde is oxidised by the enzyme ldehyde dehydrogense (LDDH) principlly within the liver. The enzyme is present in two forms, one mitochondril nd the other cytosolic nd decrese in the heptic ctivity of this enzyme, prticulrly the cytosolic form, hs been shown in lcoholic liver disese It hs been suggested tht this reduced enzyme ctivity is responsible for the rised cetldehyde concentrtions seen in lcoholics.'1 Reduced heptic LDDH ctivity could be pre-existing bnormlity which predisposes to lcoholism or lcoholic liver injury,13 but might simply be non-specific consequence of liver dmge. ddress for correspondence: Dr C Record, Gstroenterology Unit, Royl Victori Infirmry, Queen Victori Rod, Newcstle-upon-Tyne NE1 4LP. Received for publiction 11 October 1985 In order to ssess the specificity of this bnormlity to lcoholic liver disese we hve ssyed the heptic cytosolic lcohol nd cetldehyde metbolising enzymes in ptients with lcoholic liver disese nd ptients with vriety of cute nd chronic non-lcoholic liver disorders. We hve lso developed new simplified ssy to mesure blood ethnol nd cetldehyde concentrtions fter ethnol loding in ptients with the sme vriety of liver disorders. Methods PTIENTS Enzyme studies were crried out on 48 subjects who were undergoing dignostic liver biopsy. Of these, 2 hd lcoholic liver disese (LD), 2 hd non-lcoholic liver disorders (NLD) nd eight were norml controls. The ptients with LD included 14 with n estblished cirrhosis, three with heptitis but no cirrhosis, nd three with stetosis only. Seven LD ptients climed to hve bstined from lcohol for longer thn two months whilst the other 13 dmitted to or their reltives indicted continuing drinking. The ptients with NLD included seven with primry biliry cirrhosis (PBC). six with chronic ctive heptitis (CH), four with prcetmol induced liver dmge, two with cryp- 756 Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

2 Impired cetldehyde metbolism in ptients with non-lcoholic liver disorders togenic cirrhosis nd one with obstructive jundice. ctive chronic heptitis ptients ll suffered from the utoimmune vriety nd were under tretment with prednisone 5-1 mg/dy. ll NLD ptients took less thn 1 g ethnol weekly. Subjects were clssed s norml controls for the purposes of this study if they hd norml liver function tests nd norml liver histology t the time of study. Detils of ll the bove ptients re shown in Tble 1. Seven of the controls hd liver biopsies tken during intr-bdominl surgery for benign conditions when the surgeon wished to exclude liver disese. ll other liver biopsies were tken in the stndrd fshion using Trucut needle. Biopsies from the ptients with cute prcetmol poisoning were delyed until the prothrombin time hd returned to within four seconds of norml. Liver biopsy smples were divided nd one portion sent for routine histology. The other portion ws immeditely wrpped in prfilm nd plced under crushed ice. cytosolic frction ws prepred14 nd ldehyde dehydrogense ctivity ws ssyed t 3 C by the method of Blir nd Bodley15 with the ddition of pyrzole 1 mmol/i nd rotenone 6 imoli to inhibit lcohol dehydrogense nd NDH oxidse respectively. lcohol dehydrogense ctivity (DH) ws ssyed t 3 C in the reverse direction s described by Lnge16 nd lctte dehydrogense (LDH) ws ssyed by the method of Reeves nd Fimognri. 17 Protein ws mesured using the Lowry technique.18 Enzyme ctivity ws expressed in mu of enzyme ctivity per milligrm of protein present, where 1 mu corresponds to 1 nmol of substrte metbolised per minute. ll enzyme ssys were done within six hours of liver biopsy. Ethnol loding studies were undertken in 4 Tble 1 Detils of ptients undergoing liver biopsy studies Mle: Femle rtio lcoholic liver disese (n=2) 14:6 Primry biliry cirrhosis (n=7) :7 Chronic ctive heptitis (n=6) :6 Prcetmol poisoning (n=4) :4 Other non-lcoholic liver disorders (n=3) 2:1 Norml controls (n=8) 2:6 Men (rnge) ge 51 (31-66) (43-69) 4 54 (28-73) 2 28 (19-35) Cirrhotic (no) subjects, including 22 who hd the liver biopsy studies. Of the 4 subjects, 14 hd LD, 14 hd NLD nd 12 were norml controls. Only one of the LD nd none of the NLD ptients hd cliniclly detectble scites t the time of study. One LD nd two NLD ptients were tking diuretics. Five LD ptients climed bstention for longer thn two months nd nine were thought to be continuing drinkers. ll NLD ptients took less thn 1 g ethnol weekly. For ethnol loding experiments subjects were clssed s norml controls if they hd norml liver function tests, consumed less thn 1 g of ethnol weekly, nd were not known to hve liver disese. No subject hd undergone gstric surgery or ny procedure which might hve ltered the rte of gstric emptying. Detils of these subjects re shown in Tble 2. Blood ethnol nd cetldehyde concentrtions were ssyed simultneously by simplified gs chromtogrphic ssy bsed on the method of Von Wrtburg nd Ris.19 fter n overnight fst, subjects hd lrge guge butterfly plced in peripherl rm vein. Bseline blood smples were tken nd then n ethnol lod,.7 g/kg body weight ws tken orlly. The ethnol, which ws diluted in ornge juice to mke it pltble ws drunk over 1 minute period. Further blood smples were tken t 3 minute intervls over sprtte minotrnsferse (NR=-37 Ull) three hour period. Blood ws tken by llowing it to drip directly from the butterfly into 2 ml septum vils (Pierce) contining 5 ml of ice cold.61 mol/l perchloric cid (PC) nd 2 mmol freshly prepred L-cysteine. These were immeditely seled with Teflon coted rubber stoppers (Pierce & Wrmner (UK) Ltd), thoroughly mixed nd frozen on dry lkline phosphtse (NR=3-13 Ull) Prothrombin rtio lbumin (NR=34-5 gll) 67 (2-144) 15 (63-514) 84% (58-1) 39 (3-48) 9 (43-23) 664 ( ) 86% (74-1) 41 (37-44) 43 (18-93) 15 (42-141) 97% (85-1) 41 (38-46) 1868 (123-58) 19 (81-142) 63 (48-74) 2 91 (31-19) 128 (67-169) 47 (34-6) 23 (12-34) 68 (27-12) 47% (29-65) 44 (39-48) 82% (74-1) 39 (37-42) 757 Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

3 758 Tble 2 Detils of ptients undergoing ethnol loding studies Men (rnge) Mtthewson, l Mrdini, Brtlett, nd Record sprtte Mle: mino- lkline Femle Cirrhotic trnsferse phosphtse Prothrombin lbumin rtio ge (no) (NR=-37 Ull) (NR=3-13 Ull) rtio (NR=34-S5 gll) lcoholic liver disese (n=14) 9:5 47 (31-64) (11-13) 121 (47-239) 82% (74-1) 38 (3-42) Primry biliry cirrhosis (n=6) :6 6 (43-72) 4 95 (43-23) 713 (26-147) 95% (85-1) 37 (27-43) Chronic ctive heptitis (n=4) :4 53 (3-73) 49 (18-193) 18 (65-141) 1% 39 (37-44) Prcetmol poisoning (n=4) 1:3 3 (19-4) 1612 (123-58) 1 (6-128) 36% (16-5) 39 (36-45) Norml controls (n=12) 6:6 42 (24-6) 19 (1-32) 67 (42-121) ice fter the ddition of the internl stndrd, 1-propnol (1 1tmol) which ws freshly prepred for ech ssy. The quntity of blood collected (bout 2 ml; 2 drops) ws determined by weighing. For nlysis, smples were heted to 6 C for 3 minutes nd 1. ml of hed spce gs ws injected onto the GLC column. Crlo-Erb model FV 35 gs chromtogrph fitted with flme ionistion detector nd glss column (2 5 x 3 mm ID) pcked with poropk Q 8-1 mesh ws used. Operting conditions were s follows:- injector port, detector temperture nd column temperture 15 C; gs flow rtes: nitrogen crrier gs 3 ml/min, hydrogen Fig _ -1 - o -8.., -6 l.-c n.')i t r 8 S: cetldehyde concentrtion (,umol/ 1) 3 mllmin nd ir 24 ml/min. Detector sensitivity ws lx 1-2 depending on the smple, while retention times for ethnol, cetldehyde nd 1- propnol were 1.5, 2*5, nd 6-3 minutes respectively. Smples were injected into the column with 1 ml 2 pressure lok gs syringe (Precision Smpling Corportion US) which ws heted to 6 C before smpling to prevent condenstion of the smple within the syringe brrel. The output from the chromtogrph ws displyed on strip chrt recorder. Pek res were determined using n electronic integrtor (Inftronics (UK) Model 38). The ethnol, cetldehyde nd 1-propnol were 6 _ 6o Recovery from sline 5. Recvery from blood.4 4 Co e oF Recovery curves for cetldehyde nd ethnolfrom sline nd blood Ethnol concentrtion (mmol /l ) Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

4 Impired cetldehyde metbolism in ptients with non-lcoholic liver disorders well resolved by the GC, nd there ws no interference from endogenous compounds in the blood. STNDRD CURVES ND RECOVERY STUDIES Stndrd curves were constructed by spiking sline nd blood with ethnol nd cetldehyde in the concentrtion rnges mmol/l nd 1-1 iimol/l respectively. For ech stndrd curve the ethnol/propnol nd cetldehyde/propnol pek re rtios were clculted nd plotted ginst the mounts dded, s shown in Figure 1. For ech blood smple, the concentrtions of ethnol nd cetldehyde were determined by clcultion of pek re rtios nd interpoltion on the stndrd curves using the slope nd intercept of the line of best fit obtined by regression nlysis. Stndrd curves were run for ech ssy. The recovery of ethnol nd cetldehyde from blood ws very similr to the recovery from sline (Fig. 1). The recovery of cetldehyde (16 [tmol/l) dded to sline nd blood in the presence nd bsence of 2 mmol/l ethnol ws lso studied. The recovery of cetldehyde from sline, blood nd from blood plus 2 mmol/l ethnol were respectively , 16-4±.6 nd 16.6±*5 imolli (men±se, n=5). The results show tht there ws no non-enzymtic formtion of cetldehyde from ethnol, nd tht there were no losses of cetldehyde during the course of the ssy. The reproducibility of the method with respect to 3 r I- 25 E F 1 Q 5 I- F F cetldehyde ws exmined in nine smples to which cetldehyde hd been dded to finl concentrtion of 1,umol/l. The coefficient of vrition ws found to be 9 7% (rnge *1 ZmoUl, men=1.3, SE=.33). To increse the precision of the ssy triplicte blood smples were ssyed t ech time point during the study. ll subjects gve their informed consent nd the experimentl protocol ws pproved by the locl ethicl committee. STTISTICL METHODS Differences between mens were compred using the Student's t test. Vlues shown re mens nd the stndrd error of the men. In ll Figures * indictes p< 5 nd ** indictes p<.1. Results Figure 2 shows the reltionship between blood ethnol concentrtions nd time for ptients with lcoholic nd non-lcoholic liver disorders nd controls fter ethnol chllenge. The curves re similr lthough vlues were significntly rised t 3 minutes for the LD group. Figure 3 shows the cetldehyde concentrtion/time curves in the three study groups. cetldehyde concentrtions were significntly rised t every hlf-hourly point in LD ptients nd t 3, 6, 15, nd 18 minutes in NLD ptients. Men blood cetldehyde concen- 3 r Non-lcoholic liver disorders o---o Controls 25 F Time (min) Fig. 2 Blood ethnol concentrtionltime curves for lcoholic liver disese (n= 14), non-lcoholic liver disorders (n=14) nd controls (n= 12). (*p<.5). 2 F 15 k 1 F 5 F 759 Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

5 76 -I * lcoholic liver disese o----o Contros 2 * * ** * * i- * '-_d Mtthewson, l Mrdini, Brtlett, nd Record F Non-lhohic liver disese o----o Controls 161F u. U Trne (min) Fig. 3 Blood cetldehyde concentrtionltime curves for lcoholic liver disese (n=14), non-lcoholic liver disorders (n=14) nd controls (n=12). (*p<o5, **p<ooi). trtions (3-18 minute vlues) in ech study group re shown in Figure 4. There were significnt rises in the two ptient groups compred with controls but no significnt differences were seen between ptients with (LD nd NLD) nd without (LD nd E 2 C.o E 16, 12 4) c 4 : C M E 3.2 r E 16 I- 4) U C c V uv 'o ED l p 1 NS p 1 IQ : Controls Non-lcoholic lcoholic liver disorders liver disese Fig. 4 Men blood cetldehyde concentrtion fter ethnol in ptients with lcoholic liver disese, nonlcoholic liver disese nd control subjects NLD) cirrhosis (11*6±1-2 vs 1*9±-28 [imol/l respectively). The results of the heptic cytosolic ldehyde dehydrogense ssys re shown in Figure 5. Significnt decreses in enzyme ctivity were seen in ptients with LD, CH nd prcetmol poisoning. There ws highly significnt decrese when the NLD group s whole ws compred with the controls (p<.1; Tble 3). Both LD nd NLD ptients hd decresed lcohol dehydrogense ctivity when compred with controls (p<1 in both groups) but no decreses in lctte dehydrogense ctivity were seen in either of the groups studied (Tble 3). Heptic cytosolic ldehyde dehydrogense ctivity in LD ptients who were ctively drinking ws 7-9±i72 mu/mg compred with 12*5± 153 in the LD ptients who were currently bstining (p<2), lthough the ctivity of the ltter group ws still significntly lower thn controls (p<1). When ptients were divided into cirrhotic versus non-cirrhotic, no differences in enzyme ctivity were evident (1.7±.9 vs 1 9±1 1 mu/mg respectively). In subjects who hd both ethnol loding nd liver biopsy studies there ws significnt inverse correltion between men blood cetldehyde concentrtion during the 18 minutes fter ethnol nd ldehyde dehydrogense ctivity (Fig. 6). No such correltion ws found between men cetldehyde concentrtion nd cytosolic lcohol dehydrogense * Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

6 Impired cetldehyde metbolism in ptients with non-lcoholic liver disorders C & ** \ R.k-ck-i, wo... 6.\ 1. 14e, do 11 'IO 4-. Fig. 5 Heptic cytosolic ldehyde dehydrogense ctivity in ptients with lcoholic liver disese, non-lcoholic liver disorders nd controls. (* *p<ool). ctivity (r=-56) or men blood ethnol concentrtion nd lcohol dehydrogense ctivity (r= - 11). Discussion E D 2l E._ 2 16 Ṿ 12,,1 12 p.8 l u}.e 4,- 4 ui I 8 The results confirm tht ptients with lcoholic liver disese hve reduced cytosolic ldehyde dehydrogense ctivity They lso indicte tht Tble 3 Enzyme ctivities (mu/mg) in ptients with liver disese nd control subjects Liver Diseses Controls lcoholic Non-lcoholic (8) (2) (2) ldehyde dehydrogense 19-± ± lcohol dehydrogense ±1 Lctte dehydrogense ±21 Vlues of lcohol nd ldehyde dehydrogense (men±sem) in liver disese ptients were significntly different from controls (p<ool). I I 9. 1 I! \\CI I **SF ** ptients with vriety of non-lcoholic liver disorders hve similr bnormlity. This finding is in contrst with tht of Plmer nd Jenkinsil who studied totl ldehyde dehydrogense ctivity (includes mitochondril s well s cytosolic ctivity) in eight ptients with non-lcohol relted liver disorders nd found no significnt decrese in enzyme ctivity. Plmer nd Jenkins used gs chromtogrphic enzyme ssy but their dt show tht there is very close correltion between results from the chromtogrphic technique nd from the spectrophotometric technique used by us.2(' The differences between the results re probbly explined by the severity of the liver disese in our group, the greter number of subjects studied nd our concentrtion on the cytosolic frction where t lest in lcoholics, decreses in enzyme ctivity re more pronounced Jenkins et 12' studied heptic ldehyde dehydrogense ctivity in lcoholics who becme bstinent nd found significnt increse in enzyme ctivity. They concluded tht lcohol itself ws the cuse of depressed enzyme ctivity. lthough our bstining lcoholic liver disese ptients hd significntly higher vlues thn the ctive drinkers, they were significntly decresed 761 Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

7 762 E 24 2 o 16. -' 12 8 c 4 * *lcoholic liver disese Non-lcoholic liver disorders o Control Ir=-56. y= X Ip<Ol Heptic cystolic ldehyde dehydrogense ctivity (mu/mg) Fig. 6 Correltion between men blood cetldehyde concentrtions (3-18 min vlues) nd heptic cytosolic ldehyde dehydrogense ctivity. compred with the controls suggesting tht enzyme ctivity cn remin low in the bsence of continuing ethnol consumption. Our results lso show tht the bnormlity is not specific to lcoholics but occurs in vriety of cute nd chronic liver disorders, confirming tht it is consequence of liver disese rther thn pre-existing bnormlity which predisposes to lcoholism or lcoholic liver disese s suggested by Thoms et l.13 One might therefore expect ptients with the most severe liver dmge to hve the lowest ldehyde dehydrogense ctivity nd might therefore hve expected cirrhotics to hve lower enzyme ctivity thn non-cirrhotics but this ws not the cse. It should be remembered tht bsence of cirrhosis does not necessrily imply less severe liver dmge nd indeed some of our prcetmol poisoning ptients hd very severe dmge with mrked impirment of liver function, grossly prolonged prothrombin times nd encephlopthy. The severity of their dmge ws reflected in the lowest men ldehyde dehydrogense ctivity found in ny of the study groups. This study lso contirms tht ptients with lcoholic liver disese hve rised blood cetldehyde concentrtions fter n ethnol lod, nd suggests similr bnormlity in ptients with non-lcoholic liver disorders. It ws found impossible to dequtely sex mtch the control group with both the predominntly mle LD group nd the predominntly femle NLD group. Our control vlues, however, support published dt which suggest tht norml women hve lower blood cetldehyde concentrtions thn norml men fter ethnol Mtthewson, l Mrdini, Brtlett, nd Record dministrtion.22 This would tend to decrese cetldehyde concentrtions in our NLD group, but despite this vlues were still significntly rised. This finding of lower blood cetldehyde concentrtions in women my lso explin why our NLD subjects tended to hve lower blood cetldehyde concentrtions thn the LD subjects. mjor criticism of cetldehyde ssys hs been the spontneous rtifctul production of cetldehyde from ethnol during the ssy. The rpid (5-1 sec) quenching of blood in percloric cid contining L-cysteine ws found to be essentil to prevent this while in ddition the subsequent seling nd freezing of the smple on solid crbon dioxide ws necessry to void losses of cetldehyde. Recovery studies confirmed tht in the present ssy these were not significnt problems. The refinements in ssy technique could ccount for our finding of lower cetldehyde concentrtions thn previously reported.1 Like Plmer nd Jenkins" we found no evidence of impired ethnol metbolism in lcholic liver disese ptients, nor did we find ny such bnormlity in non-lcholic liver disorder ptients. Pek ethnol concentrtions were significntly rised in LD but not NLD ptients. possible explntion is tht LD ptients hd ltered volumes of distribution for ethnol. This seems unlikely, however, s only one ptient hd cliniclly detectble scites t the time of study nd lthough nutritionl sttus ws not ssessed for the purposes of this study, there were no grossly obese LD ptients. It is lso unlikely tht vrying rtes of gstric emptying were responsible s we specificlly excluded subjects with previous gstric surgery nd lso ethnol is rpidly bsorbed from the stomch prticulrly in fsting subjects such s ours. lthough ll subjects ingested the ethnol within 1 minutes it is possible tht the LD ptients who were more ccustomed to tking lcoholic beverges took the ethnol over shorter period thn other subjects, nd this my hve contributed to the higher pek ethnol concentrtions in these subjects. The bsence of ccelerted ethnol metbolism in subjects with lcoholic nd non-lcoholic liver disorders suggests tht rised cetldehyde concentrtions re cused by decresed cetldehyde metbolism rther thn incresed ethnol oxidtion. Strong corrobortive evidence is provided by the significnt inverse correltion between men blood cetldehyde concentrtion nd cytosolic ldehyde dehydrogense ctivity, finding which confirms tht of Plmer nd Jenkins.11 The fct tht we ssyed only the cytosolic frction nd found n inverse correltion rises question bout the role of this prticulr isozyme in cetldehyde oxidtion. Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

8 Impired cetldehyde metbolism in ptients with non-lcoholic liver disorders 763 Jenkins et l21 suggest tht the mitochondril enzyme hs the most importnt role to ply becuse its Km vlue more closely pproximtes to the concentrtions of cetldehyde found in vivo. They suggest tht the cytosolic enzyme hs little prt to ply becuse it hs high Km vlue in the millimolr rnge. Some uthorities, however, plce the Km vlue of the cytosolic enzyme for cetldehyde s low s 32 micromoles.23 We suggest tht the cytosolic enzyme my be importnt for three resons: firstly, lthough totl heptic ldehyde dehydrogense levels re decresed in lcoholic liver disese, this decrese is virtully ll ccounted for by the cytosolic frction,12 nd s we hve shown negtive correltion between cetldehyde concentrtions nd cytosolic ctivity lone it seems highly likely tht this isozyme is t lest prtilly involved in controlling cetldehyde concentrtions; secondly, erythrocytes contin n ldehyde dehydrogense which is morphologiclly identicl to heptic cytosolic but not the mitochondril enzyme nd it is cpble of metbolising significnt quntities of cetldehyde24 25; nd finlly, the drug disulfirm, which is used s n version therpy for lcoholics, rises blood cetldehyde concentrtions by inhibiting only cytosolic ldehyde dehydrogense,26 27 gin suggesting tht the cytosolic enzyme hs significnt role to ply. The lck of correltion between lcohol dehydrogense nd ethnol concentrtion nd the significnt decrese in lcohol dehydrogense ctivity in liver disese ptients without ny ltertion in blood ethnol concentrtions suggests tht fctors other thn the ctivity of this enzyme re rte limiting during ethnol oxidtion. We conclude tht liver injury, whether the etiology is lcoholic or non-lcoholic cn result in reduced heptic cytosolic ldehyde dehydrogense ctivity, which in turn results in impired cetldehyde metbolism nd incresed blood concentrtions fter ethnol ingestion. Our results provide theoreticl bsis for the oft given dvice to ptients with non-lcoholic liver disorders to bstin from lcohol. This study ws mde possible by grnt from the Scientific nd Reserch Committee of Newcstle Helth uthority. References 1 Perin, Sclbrino G, Sess, mboldi. In vitro inhibition of protein synthesis in rt liver s consequence of ethnol metbolism. Biochem Biophys ct 1974; 366: Burke JP, Rubin E. The effects of ethnol nd cetldehyde on products of protein synthesis by liver mitochondri. Lb Invest 1979; 41: Tum DJ, Zettermn RK, Sorrell MF. Inhibition of glycoprotein secretion by ethnol nd cetldehyde in rt liver slices. Biochem Phrmcol 198; 29: Lieber CS. lcohol, protein metbolism nd liver injury. Gstroenterology 198; 79: Knop J, ngelo H, Christensen JM. Is role of cetldehyde in lcoholism bsed on n nlyticl rtifct? Lncet 1981; 2: Thoms M, Lim CK, Peters TJ. ssying cetldehyde in biologicl fluids. Lncet 1981; 2: Eriksson CJP. Elevted blood cetldehyde levels in lcoholics nd their reltives: re-evlution. Science 198; 27: Lindros KO. Humn blood cetldehyde levels: with improved methods, clerer picture emerges. lcoholism: Clin Exp Res 1982; 6: Lindros KO, Stowell, Pikkrinen P, Slspuro M. Elevted blood cetldehyde in lcoholics with ccelerted ethnol ethnol elimintion. Phrmcol Biochem Behv 198; 13: Korsten M, Mtsuzki S, Feinmn L, Lieber CS. High blood cetldehyde levels fter ethnol dministrtion. Differences between lcoholics nd nonlcholic subjects. N Engl J Med 1975; 292: Plmer KR, Jenkins WJ. Impired cetldehyde oxidtion in lcoholics. Gut 1982; 23: Jenkins WJ, Peter TJ. Selectively reduced heptic cetldehyde dehydrogense in lcoholics. Lncet 198; 1: Thoms M, Hlsll S, Peters TJ. Role of heptic cetldehyde dehydrogense in lcoholism: demonstrtion of persisting reduction of cytosolic ctivity in bstining ptients. Lncet 1982; 2: Jenkins WJ, Peters TJ. Mitochondril enzyme ctivities in liver biopsies from ptients with lcoholic liver disese. Gut 1978; 19: Blir H, Bodley FH. Humn liver ldehyde dehydrogense: prtil purifiction nd properties. Cn J Biochem 1969; 47: Lnge LG, Sytkowski J, Vllee BL. Humn liver lcohol dehydrogense. Purifiction, composition nd ctlytic fetures. Biochemistry 1976; 15: Reeves WJ, Fimognri GM. Lctte dehydrogense. Method Enzymol 1966; 9: Lowry OH, Rosebrough NJ, Frr L, Rndll RJ. Protein mesurement with the folin phenol regent. J Biol Chem 1951; 193: Von Wrtburg JP, Ris MM. Determintion of cetldehyde in humn blood. Experimenti 1979; 35: Plmer KR, Jenkins WJ. n improved method for the determintion of ldehyde dehydrogense in humn liver biopsies using gs chromtogrphy. Clin Chim ct 1981; 115: Jenkins WJ, Ckebred K, Plmer KR. Effect of lcohol consumption on heptic ldehyde dehydrogense ctivity in lcoholic ptients. Lncet 1984; 1: rthur MJP, Lee, Wright R. Sex differences in the Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.

9 764 Mtthewson, l Mrdini, Brtlett, nd Record metbolism of ethnol nd cetldehyde in norml subjects. Clin Sci 1984; 67: grwl DP, Dethling J, Wolken S, Hrd S, Goedde HW. Sub-cellulr distribution nd properties of ldehyde dehydrogense isozymes in utopsy livers from normls nd lcoholics. lcoholism: Clin Exp Res 1982; 6: Inoue K, Fukung M, Ymsw K, Komur S. Uptke nd oxidtion of cetldehyde by intct humn erythrocytes. Biochim Biophys ct 1983; 759: Mring J, Weignd K, Brenner HD, Von Wrtburg JP. ldehyde oxidizing cpcity of erythrocytes in norml nd lcoholic individuls. lcoholism: Clin Exp Res 1982; 6: Greenfield NJ nd Pietruszko R. Two ldehyde dehydrogenses from humn liver. Isoltion vi ffinity chromtogrphy nd chrcteriztion of the isozymes. Biochim Biophys ct 1977; 483: Inoue K, Fukung M, Ymsw K. Effect of disulphirm nd its reduced metbolite, diethyldithiocrbmte on ldehyde dehydrogense of humn erythrocytes. Life Sci 1982; 3: Gut: first published s /gut on 1 July Downloded from on 13 My 218 by guest. Protected by copyright.