A szétkapcsoló fehérjék (UCP-ék) szerepe a hő és testsúly szabályozásban, különös tekintettel a hidegadaptációt követő glikogén felszaporodásra = The role of uncoupling proteins (UCPs) in the regulation of body weight and temperature with special regard to the glycogen repletion after cold exposure

Patkanyokat hidegnek tettunk ki, majd "reakklimaltuk" őket, visszahelyezve semleges hőmersekletre. A zsirsav es glukoz anyagcsere valtozasat elemeztuk a szerumban, barna es feher zsirszovetben (BAT, WAT), valamint az izomban. Reszletesen az acetil-Coenzim A karboxilaz es az ATP-citrat liaz lipogenikus enzimeket vizsgaltuk. A BAT-ban mindket enzim eseten mind a total enzim kifejeződese, mind annak foszforilezettsegi foka szembetűnően nőt, mig a WAT-ban az ellenkező tortent. Ez volt ervenyes a ket szervben ezen enzimek aktualis aktivitasara es az in vivo zsirsav szintezisre. Osszefoglalva, a WAT, csokkentve sajat szintetikus aktivitasat, kollaboral a BAT-tal. Tehat, igenis van a BAT-on kivul szerv is, amely reszt vesz az adaptiv "non-shivering" termogenezisben. Korabban kozoltuk a glikogen tartalom 14-szeres emelkedeset patkany BAT-ban a rekklimacios periodusban. Kesőbb kimutattuk a GLUT4, a UCP1 feherje kifejeződesenek emelkedeset es a UCP3 csokkeneset (ellentetben azzal, hogy a UCP3 mRNS szintje is egyutt nőt a UCP1-evel). Ujabban megallapitottuk, hogy bar hidegben a Se inzulin es glukoz csokkent, a glukoz felvetel a BAT-ba nőt. Magyarazatul, az inzulin jelatvivő kaszkad elemeinek fokozott kifejeződeset (Akt-P, GSK3-P) talaltuk, specifikusan a BAT-ban (pl. az izomban nem). Ez megmaradt a reakklimacios periodusban is, mikozben a Se inzulin a kontroll fole emelkedett. Ezek magyarazzak a glikogen szint altalunk előszor megfigyelt enormis felszaporodasat a BAT-ban. | Rats were exposed to cold and then reacclimated to neutral temperature. The changes of fatty acid (FFA) and glucose metabolism in the sera, brown- and white adipose tissues (BAT, WAT) and muscle were examined. BAT proteins showing expression marked changes, acetyl-CoA carboxylase and ATP-citrate lyase were studied in details, involving WAT and muscle. The expression of both the total and phosphorylated forms of lipogenic enzymes increased in cold, while the opposite happened to WAT. The enzyme activities, and the in vivo FFA synthesis changed in same. It seems that WAT, by decreasing its own synthetic activity collaborates with BAT in thermogenesis. Thus, does exist organ other than BAT, playing role in the non-shivering thermogenesis. We reported a 14-fold increase of glycogen in BAT of rats in the reacclimation. Then we compared the UCP1 and UCP3 mRNA and protein expression. After cold exposure, the mRNA and protein content of UCP1 increased parallel, while the UCP3 protein decreased, contrary to its own mRNA. Recently we investigated further the reacclimation period. In cold, despite the decreased serum insulin and glucose, the glucose uptake into BAT increased. The molecular basis of this increased insulin sensitivity is the enhanced expression of insulin signaling cascade specifically in BAT (Akt-P and GSK3-P in BAT, but not in muscle) in cold. The overexpressions of signaling proteins were maintained in reacclimation, while the serum insulin increased above control.