Zhang G X, Lai J H, Jia T W, Wang W Z, Wang J Y
Department of Gastroenterological Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China.
Nutrition. 1997 Jul-Aug;13(7-8):652-5. doi: 10.1016/s0899-9007(97)83009-2.
Exogenous epidermal growth factor (EGF) markedly increases the in vivo uptake of glutamine by small intestine during total parenteral nutrition (TPN). Since glutamine is the major oxidative fuel for the small intestine and is synthesized mainly in skeletal muscle, we investigated whether EGF would induce changes in the activity of the enzymes that mediate glutamine degradation (glutaminase) and synthesis (glutamine synthetase) in the two tissues. Male Sprague Dawley rats were randomized into three groups: group I (chow) were fed rat chow and water and libitum, group II (TPN) received a standard formula of TPN, and group III (TPN-EGF) received the same TPN as group II and injections of EGF (0.1 microgram/ gm body weight (bw)) subcutaneously twice daily. TPN was given for 2 wk; when EGF was administered along with TPN, the glutaminase activity of intestinal mucosa and the glutamine synthetase activity of skeletal muscle were increased, respectively, by 25% and 24% (P < 0.05, versus TPN group). These data suggest a mechanism whereby EGF enhances the intestinal utilization of glutamine by changing the activities of glutamine metabolic enzymes in the small intestine and skeletal muscle during TPN.
外源性表皮生长因子（EGF）在全肠外营养（TPN）期间可显著增加小肠对谷氨酰胺的体内摄取。由于谷氨酰胺是小肠的主要氧化燃料，且主要在骨骼肌中合成，我们研究了EGF是否会引起这两种组织中介导谷氨酰胺降解（谷氨酰胺酶）和合成（谷氨酰胺合成酶）的酶活性发生变化。雄性Sprague Dawley大鼠被随机分为三组：第一组（正常饮食组）自由进食大鼠饲料和饮水；第二组（TPN组）接受标准配方的TPN；第三组（TPN-EGF组）接受与第二组相同的TPN，并每天两次皮下注射EGF（每克体重0.1微克）。TPN持续给予2周；当EGF与TPN同时给予时，肠黏膜的谷氨酰胺酶活性和骨骼肌的谷氨酰胺合成酶活性分别增加了25%和24%（与TPN组相比，P<0.05）。这些数据提示了一种机制，即EGF通过在TPN期间改变小肠和骨骼肌中谷氨酰胺代谢酶的活性来增强小肠对谷氨酰胺的利用。
