Johnson L R, Dudrick S J, Guthrie P D
Am J Physiol. 1980 Nov;239(5):G400-5. doi: 10.1152/ajpgi.1980.239.5.G400.
Exogenous secretin and cholecystokinin (CCK) have been shown to stimulate the growth of the exocrine pancreas. To conclude that a hormone produces an effect under normal physiological conditions, one must demonstrate that the endogenous hormone also produces the action in question. To release endogenous secretin 0.01 N HCl was continuously infused into the duodenums of eight rats for 5 days. Sixteen animals were prepared with catheters inserted 1 cm below the pylorus. The other eight animals were infused with PO4 buffer, pH 7.5. The infusion rate for both groups was 2 ml/h. Animals were killed at the end of 5 days, and the oxyntic gland mucosa and pancreas were examined. Pancreatic weights, DNA synthesis, DNa, RNA, and protein content were significantly increased in rats receiving acid. An identical experiment was set up to release endogenous CCK. In this experiment eight rats received a solution containing 50 mM phenylalanine and 50 mM tryptophan. The controls received the caloric equivalent in glucose. At the end of 1 wk the pancreases of the rats infused with amino acids averaged 405 (P < 0.001) heavier than the controls. Similar increases occurred in DNA, RNA, and protein content. These studies suggest that endogenous secretin and CCK can be released in amounts sufficient to stimulate growth.
外源性促胰液素和胆囊收缩素（CCK）已被证明能刺激外分泌胰腺的生长。要确定一种激素在正常生理条件下产生某种作用，必须证明内源性激素也能产生该相关作用。为了释放内源性促胰液素，将0.01N盐酸持续输注到8只大鼠的十二指肠中，持续5天。16只动物在幽门下方1厘米处插入导管。另外8只动物输注pH 7.5的磷酸盐缓冲液。两组的输注速率均为2毫升/小时。5天结束时处死动物，检查胃腺黏膜和胰腺。接受酸输注的大鼠胰腺重量、DNA合成、DNA、RNA和蛋白质含量显著增加。为了释放内源性CCK，进行了相同的实验。在该实验中，8只大鼠接受含有50mM苯丙氨酸和50mM色氨酸的溶液。对照组接受热量相当的葡萄糖。1周结束时，输注氨基酸的大鼠胰腺平均比对照组重405（P<0.001）。DNA、RNA和蛋白质含量也有类似增加。这些研究表明，内源性促胰液素和CCK能够以足以刺激生长的量释放。
