In vitro and in vivo thermal activation of steroid-receptor complexes from rats and ground squirrels (Spermophilus citellus).
Using 3H-labelled triamcinolone acetonide (3HTA, synthetic steroid hormone), it was shown that the in vitro time course kinetics of thermal activation of 3HTA-receptor complexes exhibited the same temperature dependence in liver cytosols prepared from hibernating ground squirrels (Spermophilus citellus) as in cytosols from the rat. When 3HTA was injected in vivo to animals hibernating with a body temperature of 3 degrees C, the activation and nuclear uptake of the in vivo formed steroid-receptor complexes proceeded at a slow rate, comparable to the one predicted by in vitro studies. In the hibernator, the results are not indicative of adaptive modifications at the level of thermal activation, but prove that steroid action does proceed at a temperature incompatible with hypothermic survival in the nonhibernator.
Zivadinović
D
D
Institute for Biological Research, Belgrade, Serbia Montenegro.
Andjus
R K
RK
D000064:Acclimatization / Q000502:physiology; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005260:Female; D006605:Hibernation / Q000502:physiology*; D006358:Hot Temperature; D007035:Hypothermia / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D012589:Sciuridae / Q000378:metabolism*; D012621:Seasons; D013045:Species Specificity; D013696:Temperature; D014222:Triamcinolone Acetonide / Q000378:metabolism*
D011965:Receptors, Glucocorticoid; C039250:triamcinolone acetonide receptor; D014222:Triamcinolone Acetonide