大鼠烫伤后肝胞浆糖皮质激素受体和酪氨酸转氨酶的变化

The changes of hepatic cytoplasmic glucocorticoid receptor and tyrosine aminotransferase after scalding in rat

成年大鼠,雌,背部用沸水烫伤,轻烫组的烫伤面积为5.3cm直径的圆面积。烫10秒。重烫组为6.5cm直径,15秒。于烫伤后1、3、6和9小时断头处死,测定血浆皮质酮(B)、肝胞浆糖皮质激素受体(GCR)和酪氨酸转氨酶活性(TAT)。结果烫后3和6小时,尽管重烫组血浆B很高,但TAT却明显低于轻烫组(P<0.001),反映了严重烫伤组靶细胞对内源性糖皮质激素(GC)的反应性降低。烫后1、3小时重烫组GCR的结合容量(R)也明显低于轻烫组,提示重烫组靶细胞对GC的反应性降低至少部分地是由于GCR减少所致。对严重烫伤时靶细胞对GC的反应性降低的可能的病理和临床意义作了讨论。

Female adult rats were scalded with their backs immersed in boiling water for 10 seconds in moderately scalded groups and 15 seconds in severely scalded groups.The scalding area was a circle with a diameter of 5.3 em in the moderate group and 6.5 em in the other.After scalding the rats were decapitated at the intervals of 1,3,6 and 9 hours.The plasma corticosterone(B),glucocorticoid receptor(GCR)and the activity of tyrosine aminotransferase(TAT)in the cytoplasmic fraction of the liver homogenates were determined.The results showed that the TAT induced 3 and 6 hours after scalding in the severe group was obviously lower than that in the moderate group(P<0.01),though the plasma B of the former was very high.This result suggests a lowered inducibility of TAT by the endogenous glucocortieoid hormone(GC),or a decreased reactivity of the target cells to GC in the severe group.Since the binding capacity(1to)of the GCR was also much lower in the severe group 1 and 3 hours after scalding,it might be suggested that the decreased reactivity of target cells to GC was at least partly resulted from the decrease in GCR.The possible pathological and clinical significance of the lowered reactivity of target cells to GC in severe scalding was discussed.