Arch. Tierz., Dummerstorf 49 (2006) Special Issue, 41-51

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1 Arh. Tierz., Dummerstorf 49 (26) Speil Issue, Deprtment of Physiologil Sienes, Fulty of Veterinry Meiine, Wrsw Agriulturl University, Wrsw, Nowoursynowsk Deprtment of Physil-Chemil Anlyses, Fulty of Animl Sienes, Wrsw Agriulturl University, Wrsw, Ciszewskiego 8 MAŁGORZATA ŁOKOCIEJEWSKA 1, JOLANTA WAGNER 2, JOANNA ZARZYŃSKA 1, MICHAŁ JANK 1, PIOTR OSTASZEWSKI 1, ANNA BURDZIŃSKA 1, TOMASZ SADKOWSKI 1, JUSTYNA OLCZAK 1, ANNA MRÓWCZYŃSKA 1 n ARKADIUSZ ORZECHOWSKI 1 Soium sorte () n sori i phosphte () ifferently moulte gluoortioi-epenent metoli effets in growing rts Astrt It is well known tht exmethsone tretment in ertin oses inues oxitive stress, insulin resistne, ietes, n musle hexi. This survey ws rrie out to investigte the effet of sorte erivtives on exmethsone-inue metoli isturnes. Experiment ws performe on 6 weeks ol mle rts. Orl ose of soium sorte (6 mg/kg.w., ) or sori i phosphte (785 mg/kg.w., ) ws given seprtely (BID) or s o-tretment with exmethsone phosphte (ily ose of 2 mg/kg.w., ). Rts were rnomly ivie into ontrol n experimentl groups n the effet of 5-y tretment without () or with,,, or omine with or with (Tretment) ws ompre with respet to inies of niml growth, somti inies n results of gluose tolerne test. The effets of 5-y tretment n 5-y reovery perio (when none of the experimentl ftors ws use) were ompre. Aministrtion of use signifint eline of serum sorte n ehyrosorte (-87%, P<.1). This ws in prt orrete y or o-tretment with (-68%, P<.1). n were of minor importne to limit -inue growth retrtion lthough they enhne sensitivity to insulin t lest t the level of gluose utiliztion (P<.1). ws superior to in sensitiztion to insulin (P<.5). signifintly rise somti inies (SI) of liver (+52%), kineys (+44%), hert (+52%) n soleus musles (+44%) ut not gstronemius musles (P>.5). In ontrst, spleen SI roppe signifintly upon tretment (-57%). After 5-y reovery perio -ltere SI-s i not return to ontrol vlues (P<.5). Neither nor ffete SI-s nor they oul reverse -inue hnges in SI-s exept whih onfine the rise of renl SI (P<.5). in ontrst to even ugmente -epenent heptomegly (P<.5). Interestingly, oth sorte erivtives effiiently inhiite -inue musle hexi t lest with respet to gstronemius musle (P<.5). Summing up, these results suggest ifferenes etween the fst n slow effets evoke y sorte in the experimentl moel of growth retrtion n musle hexi inue y n ompnie y gluoortioi-epenent ietes. Key Wors: sorte, sori i phosphte, gluoortiois, growth, musle hexi, insulin resistne Zusmmenfssung Titel er Areit: Ntriumsort () n Asorinsäurephospht () eeinflussen Glukokortikoi-hängige metolishe Prozesse ei whsenen Rtten untershielih Es ist etliert, ss Dexmethsonehnlung Dosis-hängig oxitiven Stress, Insulinresistenz, Dietes un Muskelkhexie verursht. Hier wure er Effekt von Asorterivten uf Dexmethson-usgelöste Stoffwehseluslenkungen ei 6 Wohen lten männlihen Rtten untersuht. Ntriumsort (6 mg/kg, ) n Asorinsäurephospht (785 mg/kg, ) wuren orl einzeln oer in Komintion mit Dexmethsonphospht (2 mg/kg, ) verreiht. Rtten wuren zufällig er Kontroll- zw. en Versuhsgruppen zugewiesen un hinsihtlih Whstum, Glukosetolernz un somtishen Inizes nh fünftägiger Behnlung un nh weiteren fünf Tgen Rekonsoliierung verglihen. verurshte eine signifiknte Anhme es Serumsorts un es Dehyrosorts (-87%, P<.1). Die Wirkung wure teilweise urh Ko-Behnlung mit oer (-68%, P<.1) ehoen. un egrenzten ie -verurshte Whstumsverlngsmung nur geringfügig, ogleih sie ie Empfinlihkeit zum Insulin minestens uf em Niveu er Glukosenwenung (P<.1) erhöhten. wr in er Sensiilisierung für Insulin (P<.5) üerlegen. erhöht signifiknt somtishe Inizes (SI) er Leer (+52%), er Nieren (+44%), es Herzens (+52%) un es Soleusmuskels (+44%) er niht es Gstronemiusmuskels (P>.5). Demgegenüer fiel er Milz SI erhelih nh -Behnlung (-57%). Nh 5tägiger Rekonsoliierung gingen -geänerte SI-s niht uf ie Ausgngswerte zurük (P<.5). Weer noh eeinflussten SI-s, noh

2 42 konnten sie -verurshte Änerungen er SI-s usgleihen, usgenommen em Anstieg von Nieren-SI urh (P<.5) egrenzte., im Gegenstz zu, vergrößerte sogr -hängige Heptomeglie (P<.5). Interessnterweise hemmten eie Asorterivte -verurshte Muskelkhexie, zuminestens in Bezug uf en Gstronemiusmuskel (P<.5). Zusmmenfssen zeigen ie Ergenisse Untershiee zwishen en shnellen un lngsmen Effekten in en experimentellen Moellen er -inuzierten Whstumsverlngsmung, Muskelkhexie egleitet von Glukoortioi-hängiger Dietes. Shlüsselwörter: Asort, Asorinsäurephospht, Gluokortikoi, Whstum, Muskelkhexie, Insulinresistenz Introution It is well oumente tht exess of gluoortiois les to growth retrtion n musle hexi (DARDEVET et l., 1995; HASSELGREN, 1999). Dexmethsone, syntheti gluoortioi is thus frequently use to ttenute growth n to trigger musle wsting (SAVARY et l., 1998; ORZECHOWSKI et l., 2; ORZECHOWSKI, 22; MA et l., 23). The moleulr sis for gluoortioiepenent musle trophy is omplex n inlues oxitive stress (ORZECHOWSKI et l., 2), resistne to insulin (DARDEVET et l., 1998), tivtion of protesoml system (ATTAIX et l., 1998) n higher tivity of myosttin (MA et l., 21; 23). In ontrst, insulin plys importnt role in the mintenne of whole-oy nolism. Previously, we reporte positive effet of soium sorte on insulinmeite mitogeniity n ell viility in mononuler L6 musle ells (ORZECHOWSKI et l., 22). Similrly sorte erivtive, nmely sori i 2-phosphte ws shown to elerte moleulr mehnism of terminl ifferentition of L6 myolsts n musle formtion in ell ulture moel (MITSUMOTO et l., 1994). It ws lso emonstrte tht soium sorte rise phosphoryltion of Akt n -Jun in the sme unifferentite musle ells (ORZECHOWSKI et l., 25). On one hn, severl stuies inite tht either gluoortiois exess, or lk of insulin (insulin epenent ietes mellitus, IDDM) or insulin resistne (non-insulin epenent ietes mellitus, NIDDM) ll trigger oxitive stress (ERIKSSON n KOHVAKKA, 1995; BAKER et l., 1996; PEREIRA et l., 1999; ORZECHOWSKI et l., 2; CHOI et l., 23). On the other hn, vitmin C supplementtion often results in strenghthening the ntioxint efenses (ARRIGONI n TULLIO, 22; EGUCHI et l., 23). Therefore, the purpose of this stuy ws to estlish if sorte erivtives oul prevent isturnes inue experimentlly y high ose of exmethsone in growing rts. We ssume tht t lest some of exmethsone-inue effets (growth retrtion, insulin resistne or musle hexi) were in usl reltionship with oxitive stress. Furthermore, our own oservtions n ville literture t inite tht sorte moultes regultory proesses where signls from insulin n insulin-like growth ftors (IGF-s) re tivte n trnsue to trget genes (PETERKOFSKY et l., 1991; GOSIEWSKA et l., 1994; MAHMOODIAN n PETERKOFSKY, 1999; ORZECHOWSKI et l., 25). IGF-ining proteins (IGFBP-s) re often inite to ntgonize IGF-sepenent growth promoting effets. There is eviene tht gluoortiois upregulte igfp-1 gene, wheres insulin ts in opposite wy to stop exmethsone-epenent stimultion of igfp-1 gene promoter tivity (SUH et l., 1994; SUH n RECHLER, 1997). Thus, in theory insulin tion oul e ugmente y sorte so tht it oul inhiit gluoortiois in negtive ontrol of niml growth. It seems neessry to etermine the wy of tion, effetive onentrtions n whether vitmin C n

3 43 shelter insulin tivity impire y gluoortiois (seonry gluoortioiepenent ietes). As ove-mentione it ws ssume, tht insulin plys onsierle noli funtion, therefore with regr to evelopmentl proesses the positive effet of vitmin C might e ssoite with the positive reltionship etween vitmin C n iologil effets of insulin. Vrious erivtives of sori i re ommerilly use s ietry supplements to prevent foos oxition. Asori i phosphte () is preferre to fortify fees sine sorte () is relese from in reltively slow n onstnt rte y the tion of lkline phosphtse (AP) present in gut muos. In ontrst, sorte is sore lmost instntly from the GI trt n within minutes is exrete with urine. By the iniviul use of equimollr quntities of n s fee supplements or intrgstri oli it is esy to ifferentite etween long-term versus short-term effets of sorte. In this experiment, we eie to fin out how some vitmin C erivtives (soium sorte n sori i phosphte) woul slow own the toli effet of exmethsone n how they n mplify insulin tion in exmethsone-inue insulin-resistnt stte. Mteril n methos Animls Polish Ministry of Agriulture rules for niml welfre were followe uring these experiments. All experimentl proeures on nimls were pprove y the Lol Ethi n Animl Welfre Commission of the Wrsw Agriulturl University. Fourweek of ge (young) Wistr mle rts (n=12) were purhse from Institute of Animl Physiology n Animl Feeing, Polish Aemy of Sienes (Jłonn ner Wrsw, Poln). Stnr lortory roent how (Wytwórni Psz, Anrzej Morwski, Kyni, Poln) ontining 13 MJ kg -1 metolizle energy n 21.2% w/w rue protein ws provie twie y. Any remining uneten foo ws weighe n fee intke ws lulte ily. Wter ws provie liitum. Eh niml ws house iniviully in ontrolle environmentl onitions (22 o C, 75% humiity, 12:12-h light-rk yle perio strte 8: AM). After 2-week limtiztion perio, the Dex tretment ws egun. At this point the rts were 6 weeks of ge (18-2 g). Beuse Dex lters foo intke, ontrol nimls were pirfe the verge ily mount onsume y the orresponing -trete group. Two 5 ys experimentl perios - Tretment n Reovery were investigte. From our preliminry experiments (ORZECHOWSKI et l., 2, 22) we foun tht exmethsone tretment le to musle hexi n insulin resistnt stte in growing rts. To hieve these, -trete rts reeive 1 ml of exmethsone isoium phosphte (Sigm, St. Louis, MO, USA) issolve in sline (.85% w/v NCl) given twie y t 8. AM n 4. PM (1. ml) y intrgstri tue in ily ose of 2 mg/kg.w. y -1 uring 5 onseutive ys. After 5 ys of tretment one set of rts (Tretment, ) ws kille n issete, n nother set of rts (Reovery, /REC) ws kille fter 5 ys of the reovery perio. Afterwrs, ontrol nimls (Tretment, plus Reovery, /REC) reeiving 1 ml of sline (vehile,.85% NCl) were fe the sme mount of foo s ws onsume y its exmethsone-trete pir mte uring previous y. Similrly, nimls from other groups were given the verge ily mount of foo eing eten y -trete nimls. Soium sorte () n sori i phosphte () were

4 44 purhse from Sigm (St. Louis, MO, USA). n were given iniviully or s o-tretment with t ose of 6 mg/kg.w y -1 n 785 mg/kg.w y -1, respetively. Either ftor ws issolve in istille-eionize wter (Aqu pro injetione, Polphrm S.A., Poln) n introue to rts y the intrgstri tue in volume of 1 ml. Time-sheule ws the sme s for. Twelve rnomize groups of nimls (, /REC,, /REC,, /REC, P-, P-/REC, -, -/REC, P--, P-- /REC) were forme (n=1). Foo intke, oy weight n wet orgn weight t were use to lulte somti inies: oy weight gin [finl oy weight - initil oy weight, BWG in grms], reltive oy weight gin [(BWG/initil oy weight) 1, RBWG in perentge], speifi growth rte [(ln finl oy weight ln initil oy weight) 1, SGR in perentge], protein effiieny rtio [ily protein intke/ily BWG, PER], instntneous foo intke [(ily ry foo intke/oy weight) 1, IFI in perentge] n somti inies [(orgn wet weight 1/oy weight), SI in perentge]. Wter intke ws lso lulte n onfronte with PCV to hek for ehyrtion hzr. Biohemil nlyses Animls were nesthetise y intrperitonel injetion of.3 ml pentoritl soium slt (Pentoritlum 26.7 mg/ml; Pentoritlum Ntrium 133/ml, Moritl, Biowet, Pułwy, Poln). Aominl vity ws opene n loo smples were ollete into heprinize syringes iretly from the ominl ort of eh niml. Immeitely fterwrs, selete orgns were issete, wshe with ie-ol sline, lotte on sorent pper, weighe, overe with luminium foil n ple into liqui nitrogen. The loo smples kept on ie were ivie into seprte tues n whole loo, loo plsm n loo ells (fter entrifugtion t 8 g, 1 min) were eh frozen t -8 o C. Pke Cell Volume (PCV) ws etermine routinely with miropillr metho. Asorte n oxiize form of sorte (ehyrosorte) were ssye in loo plsm y HPLC metho esrie y WANG et l. (1995) n RUMELIN et l. (1999). Determintion of gluosuri To hek whether nimls re ieti (ietes mellitus) every morning urine smples from eh niml (from tretment n reovery perios) trete iniviully with or -o-trete were ollete on regent strips (Keto-Distix, Byer B. V. Division Dignostis, Brussel, Belgium) n gluose presene ws esily reognize y olor initor. Gluose tolerne test One y prior to the en of Tretment or Reovery perio ll nimls (12 groups, 12 nimls in totl) were iniviully teste for insulin resistne y the use of gluose tolerne test. Initilly, fsting gluose onentrtion in the whole loo ws etermine. Five minutes lter 1 ml of 4% (w/v) gluose wter solution (Pliv, Poln) ws given intrgstrilly ( time) n 15, 3, 6, 9 n 12 minutes lter gluose level ws etermine in the miroliter volumes of loo ollete from til vein. The mesurement ws performe with Gluor II GT-162 pprtus (KDU Corportion, Kyoto, Jpn).

5 45 Sttistil evlution Results were sttistilly evlute using one wy ANOVA n Tukey's multiple rnge test or two-wy ANOVA with Benferroni post test y GrphP Prism TM version 3.3 softwre (GrphP Softwre In., Sn Diego, CA, USA). Results re expresse s men + SEM n vlue of P<.5 ws etermine to e signifint, P<.1 s highly signifint n P<.1 s very highly signifint. Results Effet of tretment on gluosuri. It shoul e pointe out tht gluose ws etete in urine of growing rts 2 ys fter the initition of tretment (t not shown). When ws ministere with or gluosuri ws ignose one y lter (t not shown). Gluose isppere from urine one y following tretment (t not shown). Anywy, urine tests onfirme tht t the ose of 2 mg/kg.w. y -1 uses seonry ietes. Dieti stte reesses immeitely fter withrwl from the tretment. Effet of 5-y n or o-tretments on growth inies. Growth inies erese mrkely in nimls, prtiulrly in the 3 r y of exmethsone tretment. IFI roppe mrkely upon tion from 13.4% t y to 1.67% + 1. t y 3 of tretment (-2%, P<.5). At the sme time points (y 1 vs. y 3 of -tretment) other ynmi growth inies were impire s follows: SGR roppe y 21% (P<.1), RWBG y 168% (P<.1), while PER y 358% (P<.1). In ontrst to SI-s, fter itionl 5-y reovery perio IFI, SGR, RWBG n PER returne to ontrol levels (P>.5, t not shown) pointing towr trnsient hrter of -inue growth retrtion. Neither, nor influene fee intke onfine y (P>.5, t not shown). In ontrst to, however, ws shown to iminish IFI in verge y 1% in omprison to uring reovery perio (P<.1, t not shown). ministrtion le to the progressive loss of oy weight illustrte y erese RBWG. The ltter eme negtive (-4.68% +.59, P<.5) strting from the 3 r y of tretment ut lmost returne to ontrol vlue (3.2% + 1.2, P>.5) the y fter the en of tretment (1 st y of reovery perio). Agin, neither of erivtives oul ffet -inue negtive effet on RBWG (P>.5, t not shown). When t were plotte on XY grphs the slopes of RBWG n SGR urves fit lmost ientil. Agin, similrly to RWBG SGR eme negtive (-4.81% +.61, P<.5) t 3 r y n eme positive t 1 st y of reovery (2.91% , P>.5). These finings were itionlly reflete y the signifint fll of protein effiieny rtio (from t y to t 3 r y of tretment, P<.5). Agin, next y fter removl PER rise to There ws solute lk of or effet on -inue lower PER (P>.5). From these stuies it is ler tht in growing rts n were of minor importne to limit -inue growth retrtion. In ontrst to whih signifintly elevte PER t the en of reovery perio, signifintly iminishe PER ll long the reovery perio (P<.5). These outomes our irrespetive to the enhne sensitivity to insulin use y either of the sorte erivtive (see gluose tolerne test).

6 46 Effet of 5-y n or o-tretments on metoli inies. At 5 th y of tretment, totl enogenous plsm sorte n ehyrosorte roppe signifintly from µmol/l foun in ontrol to 8.19 µmol/l in -trete rts (-87%, Fig. 1C, P<.1). Anywy, we i not oserve ny inrese in ehyrosorte even though we ssume tht sorte unerwent oxition uring -inue insulin resistnt stte (Fig. 1B). More likely sorte/ehyrosorte were egre n stright wy exrete with urine. Aition of or inompletely ut signifintly me higher serum levels of sorte/ehyrosorte t 5 th y of o-tretment (-68%, Fig. 1C, P<.5). Conentrtion [umol/l] B 3 Conentrtion [umol/l] Conentrtion [umol/l] A 2 1 C Bloo plsm sori i e e + + Bloo plsm ehyrosori i e e + + Totl loo plsm sori/ehyrosori is e e + + Fig. 1: Br hrts illustrting hnges in loo plsm onentrtions of (A) sori i; (B) ehyrosori i; (C) totl sori/ehyrosori is. Brs represent verge onentrtion + SEM etermine in loo plsm ollete fter tretment (lk) or fter reovery perio (white). Different letters inite signifint ifferenes (P<.5). Tretments inite with revition uner siss. (Blkenigrmme zu Blutplsmkonzentrtionen von (A) Asorinsäure, (B) Dehyrosorinsäure un (C) Gesmtsorin-/ehyrosorinsäuren. Blken geen ie urhshnittlihe Konzentrtion ± SEM im Blutplsm nh Behnlung (shwrz) oer nh Rekonsoliierung (weiß) n. Untershielihe Buhsten kennzeihnen signifiknte Differenzen (P<.5). Behnlungen sin n er Azisse mit Akürzungen spezifiziert) Whenever given iniviully, either or inrese sorte/ ehyrosorte serum onentrtions ut these effets were sttistilly insignifint (Fig. 1A). Interestingly, lthough n were of minor importne to limit -inue growth retrtion they enhne sensitivity to insulin (Fig. 2). It ws shown tht t 9 th n 12 th min of test the loo gluose onentrtion esene signifintly fter omine n o-tretment (Fig. 2A, P<.1). Apprently, in this regr ws ple to reue signifintly loo gluose level - strting t 15 th min, n ws mintine through the test (Fig. 2B, P<.5; P<.1; P<.1). Without o-tretment hypoglyemi effets of either or were less evient lthough remine sttistilly highly signifint (Fig. 2C, Fig. 2D, P<.1, P<.1).

7 47 A Gluose-tolerne test B Gluose-tolerne test loo gluose onentrtion [mmol/l] /REC + +/REC loo gluose onentrtion [mmol/l] ** ** * /REC + +/REC Time [min] Time [min] C Gluose-tolerne test D Gluose-tolerne test loo gluose onentrtion [mmol/l] ** ** * loo gluose onentrtion [mmol/l] ** ** * /REC /REC /REC Time [min] Time [min] Fig. 2: Figures illustrting time ourse of hnges in whole-loo gluose uring gluose tolerne tests performe in rts uring tretment n reovery perios tht hve een given (A) or plus ; (B) or plus ; (C n D) or. Averge vlues + SEM mrke with sterisks iffer signifintly (*, P<.5), highly signifintly (**, P<.1), or very highly signifintly (, P<.1) from the respetive referene vlues ifferent for A (), B (), C () n D () (Verluf er Blutglukosekonzentrtion im Glukosetolernztest ei Rtten nh Behnlung un Rekonstitution mit (A) oer plus ; (B) oer plus As-p-p; (C un D) As oer As-p-p. Durhshnittswerte ± SEM. Mit Sternhen gekennzeihnet signifiknte Untershiee zu in A un B sowie zur Kontrolle in C un D) Effet of 5-y n or o-tretments on metoli inies. Similrly to ynmi inies of growth, where n oul hrly ttenute inue ltertions, some somti inies were effiiently moulte y sorte erivtives. At the 5 th y of tretment, signifintly rise SI-s of liver (+52%, P<.1), kineys (+44%, P<.1)), hert (+52%, P<.1)) n soleus musles (+44%, P<.1) ut not gstronemius musles (P>.5). In ontrst, spleen-somti inex roppe signifintly upon tretment (-57%, P<.1). After 5-y reovery perio -meite hnges in SI-s i not ome k to ontrol vlues (P<.5). Overll, when given iniviully, neither nor ffete SI-s, nor they oul reverse -inue hnges in SI-s with the exeption of tht eepene -inue heptomegly (P<.5). This ws not the se for, whih loke up the rise in renl-somti inex (P<.5). Prtiulrly istint effet ws evoke y oth n on -inue musle hexi t lest with respet to gstronemius musle (Fig. 3E). Interestingly, in ontrst to soleus musle, oth sorte erivtives effiiently inhiite -inue fll in reltive weight of gstronemius musles (P<.5). In onlusion, we woul like to emphsize tht issoition exists etween the fst n slow effets of sorte on ynmi inies of growth, somti inies, n -inue insulin esensitiztion ssoite with the seonry ietes in growing rts.

8 48 A Hepto-somti inex [%] B Hert-somti inex [%] C Renl-somti inex [%] liver wet weight (g) x 1/oy weight (g) hert wet weight (g) x 1/oy weight (g) kineys wet weight (g) x 1/oy weight (g) D Musle-somti inex m. E Musle-somti inex m. F soleus [%] gstronemius [%] Spleen-somti inex [%] musles wet weight (g) x 1/oy weight (g) musles wet weight (g) x 1/oy weight (g) spleen wet weight (g) x 1/oy weight (g) Fig. 3: Br hrts illustrting hnges in somti inies lulte oring to the formul esrie in Mteril n methos. Brs represent verge vlues + SEM otine from post mortem mesurements fter tretment (fille lk) or fter reovery perio (empty white), respetively. Brs mrke with ifferent lower se letters iffer t lest signifintly (P<.5). Eh tretment is inite with revition lote uner siss. (Blkenigrmme zur Änerungen metolisher Inizes, errehnet entsprehen er Formel in Mteril un Methoen. Blken geen ie Durhshnittswerte ± SEM er postmortem Messungen nh Behnlung (shwrz) oer nh Rekonsoliierung (weiß). Untershielihe Buhsten kennzeihnen signifiknte Differenzen (P<.5). Behnlungen sin n er Azisse mit Akürzungen spezifiziert) Disussion 5-y ministrtion of le to progressive signifint n severe fll of growth inies in 6-weeks ol rts. These hnges were use y oth loss of petite n most likely elerte whole-oy tolism. Growth retre y ws reversile, sine the y fter the withrwl of the ynmi inies of growth inrese steily up to 5 th y of reovery perio. This ws not the se when hnges in somti inies were monitore t 5 th y of tretment n reovery perio. Reltive weights of liver, hert, kineys n soleus musles rose uring tretment wheres they eline when ws remove from tretment. Even then, however, in the 5 th y of reovery perio the somti inies were sttistilly ifferent from ontrol, untrete rts (Fig. 3). One shoul er in min tht evoke seonry ietes n wter lne ought to e seriously isture. To hek ehyrtion hzr we mnge PCV n foun no initions tht nimls were ehyrte s we ssume ue to the ompenstory wter intke tht rise onsierly (t not shown). The losses in IFI, RBWG, SGR n PER foun in growing rts were ompnie y eep fll in the verge onentrtions of plsm sorte n ehyrosorte (Fig. 3). The ltter onfirms iniretly tht inues oxitive stress. The reuing size of spleen upon tretment is onsistent with the generl wreness how effiiently gluoortiois suppress limphoi system. Anywy, the most intriguing oservtion is linke to gstronemius musle. n pprently inhiite -inue hnges in the reltive weight of the

9 49 musle. It is not ler, why we oul not notie similr effet in soleus musle. To omprehen the onsequenes of ministrtion one hs to know, tht ulk of t inites tht gluoortiois in unne slow own prentl n postntl growth (AIN et l., 25; ORZECHOWSKI et l., 22). Gluoortiois n teholmines re relese from renls in response to environmentl stress tht often ompny nimls kept inoors in high prouing frms. The sie-effet of exess gluoortiois n teholmines is the eveloping oxitive stress. The moleulr mehnisms of gluoortioi/teholmines-ssoite oxitive stress result from oth the impire ntioxint efenses (PEREIRA et l., 1999; ORZECHOWSKI et l., 2) n upregulte oxitive metolism (MANOLI et l., 25). In our stuies we i not mesure the inies of oxitive stress (it is urrently etermine) ut we i similr evlution in the pst with similr results (ORZECHOWSKI et l. 2, 22). Moreover, short- n long-term ministrtion of exogenous ortiosterone use oxitive stress in roiler hikens (LIN et l., 24, 24). Interestingly, in roilers n lying hens ietry sorte erese enogenous plsm ortiosterone n het shok protein 7 elevte y yli het stress (MAHMOUD et l., 23, 24). Some of the exmethsone-inue negtive ffets on growth re ssoite with the elevte IGFBP-s (SUH et l., 1994) n impire tion of IGF-s wheres other re elieve to e onsequene of higher level of myosttin protein (MA et l., 23). Regrless of the unerlying mehnism of tion sorte erivtives were of minor importne to orret inue growth restrition. The ruil ftor for improvement ws pprently the reovery perio (P<.5). However, n moertely moulte some of the somti inies; prtiulrly they lowere -inue resistne to insulin. In onlusion, we emonstrte tht orl loing inue metoli hnges suh s growth retrtion, peripherl loo hyperglyemi, n reltive inrese in liver, hert, kineys n soleus musles wet weight. The ove-mentione ltertions in growth inies resulte from the progressive loss of oy weight n musle hexi. This ws not the se for tigh musles (prtiulrly soleus musle ws not ffete). To explin the oserve flututions in orgn wet weight in reltion to oy weight it is importnt to stress tht other musles hve to e severely ffete y. Totl sorte plsm onentrtion mrkely roppe in -trete nimls (Fig. 2, P<.1). Efforts to orret -meite toli effet y the o-tretment with or le to slight ut not spetulr improvement. This oul e onsequene of high, su-toxi ose of n/or other not oxint epenent mehnisms of tion in growing rts. Anywy, we oserve tht n signifintly vne sensitivity to insulin, while itionlly hs n vntge to lower -inue verge loo gluose level. The ltter n other enefiil effets of s we suppose were onsequene of slow n reltively ontinuous relese of this wter solule ntioxint from GI, sine relese sorte ws reporte to itionlly moulte the tivity of phosphtses (EGUCHI et l., 23). Further stuies re neee to evlute whether other ntioxints (vitmin E, α- lipoi i, turine et.) posses ntitoli properties to ontrol or prevent - or stress-inue growth onstrints. Otherwise, we mit tht t lest prt of the toli tivity of originte from lterntive resons other thn oxitive stress.

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