Majumdar A P, Edgerton E A, Arlow F L
Research Service, Veterans Administration Medical Center, Allen Park, MI 48101.
Biochim Biophys Acta. 1988 May 12;965(2-3):97-105. doi: 10.1016/0304-4165(88)90043-8.
The relationship between tyrosine kinase activity and cellular proliferative activity was investigated in the gastric mucosa. For the purpose of comparison, the liver and the pancreas were also included. Groups of 2-, 14- and 22-month-old male Fischer-344 rats were used. Tyrosine kinase activity was determined in the membrane fraction (30,000 x g pellet) utilizing a synthetic polymer, Glu-Tyr (4:1), as substrate. Cellular proliferative activity was assessed by measuring ornithine decarboxylase in the 20,000 x g supernatant. In all age groups, gastric mucosal tyrosine kinase activity was found to be 10-20-fold higher than in the liver or pancreas. In addition, gastric mucosal tyrosine kinase activity in 22-month-old rats was 35-70% higher than in their 2- and 14-month-old counterparts. Gastric mucosal ornithine decarboxylase activity also followed essentially the same pattern as that of tyrosine kinase in that the highest activity was observed in 22-month-old rats. Increased gastric mucosal proliferative activity in 22-month-old rats was also associated with increased tyrosine-phosphorylation of a mucosal membrane protein with an apparent Mr of 53,000. An opposite phenomenon occurred in the pancreas whose proliferative activity was found to be the lowest. It is concluded that the age-associated changes in gastric mucosal proliferative activity are accompanied by parallel alterations in tyrosine kinase activity. Tyrosine-phosphorylation of a 53 kDa membrane protein may play a role in the regulation of cell proliferation.
研究了胃黏膜中酪氨酸激酶活性与细胞增殖活性之间的关系。为作比较，还纳入了肝脏和胰腺。使用了2月龄、14月龄和22月龄的雄性Fischer-344大鼠组。利用合成聚合物Glu-Tyr（4:1）作为底物，测定膜组分（30,000×g沉淀）中的酪氨酸激酶活性。通过测量20,000×g上清液中的鸟氨酸脱羧酶来评估细胞增殖活性。在所有年龄组中，发现胃黏膜酪氨酸激酶活性比肝脏或胰腺中的高10 - 20倍。此外，22月龄大鼠的胃黏膜酪氨酸激酶活性比2月龄和14月龄的大鼠高35 - 70%。胃黏膜鸟氨酸脱羧酶活性也基本遵循与酪氨酸激酶相同的模式，即在22月龄大鼠中观察到最高活性。22月龄大鼠胃黏膜增殖活性增加还与一种表观分子量为53,000的黏膜膜蛋白酪氨酸磷酸化增加有关。胰腺中则出现相反现象，其增殖活性被发现是最低的。结论是，胃黏膜增殖活性随年龄的变化伴随着酪氨酸激酶活性的平行改变。一种53 kDa膜蛋白的酪氨酸磷酸化可能在细胞增殖调节中起作用。
