Lerner R L, Porte D
J Clin Invest. 1972 Aug;51(8):2205-10. doi: 10.1172/JCI107028.
Recent studies have suggested that secretin, like glucose, stimulates a rapid insulin response from a small storage pool. In order to evaluate the mechanism of the secretin-stimulated insulin response, small (15 U) rapidly administered intravenous injections (pulses) of secretin were given before, during, and after a 20 hr 300 mg/min glucose infusion. Contrary to previous studies demonstrating that the acute insulin response to a small (5 g) pulse of glucose given 45 min after the start of the glucose infusion was significantly diminished compared to the response to the preinfusion pulse, the acute insulin response (2-5 min Deltaimmuno-reactive insulin muU/ml) to 15-U secretin pulses exhibited a greater than twofold increase (before: 31.1+/-15.4; during: 71.2+/-40.4, muU/ml, mean +/-SD, P < 0.02). The increased response to secretin was also found after 20 hr of continuous glucose infusion, but was not observed 1 hr after cessation of the infusion when plasma glucose levels returned to control values. Thus, this increased response to secretin was glucose dependent. Four 150-U secretin pulses given at 30 min intervals elicited progressively and significantly diminished acute insulin responses with each succeeding pulse, consistent with depletion of the small storage pool. Similar to the observation that the magnitude of the insulin response to secretin was glucose dependent, the glucose-stimulated output appeared to be secretin dependent. Thus the acute insulin response to 5 g glucose was increased after secretin pretreatment (presecretin: 34.9+/-14.8; postsecretin: 50.5+/-22.5 muU/ml. P < 0.02) which suggests that secretin may either enlarge the storage pool stimulated by glucose or increase its sensitivity. The effect of epinephrine and propranolol on acute insulin responses to secretin and glucose was also different. 15-U secretin pulses were unaffected by infusions of either epinephrine (pre: 31.6+/-17.9; during: 27.8+/-16.6 muU/ml) or propranolol (pre: 12.8+/-8.4; during: 10.7+/-5.5 muU/ml). The results of these studies indicate that although both glucose and secretin stimulate a rapid insulin response, these responses are easily differentiated. The data suggest that glucose and secretin stimulate functionally separate storage pools of insulin, but that the acute response to either stimulus is partly determined by exposure to the other.
最近的研究表明，促胰液素与葡萄糖一样，能从小储存池中刺激快速的胰岛素反应。为了评估促胰液素刺激胰岛素反应的机制，在20小时300毫克/分钟的葡萄糖输注之前、期间和之后，快速静脉注射小剂量（15单位）的促胰液素（脉冲式）。与之前的研究相反，之前的研究表明，在葡萄糖输注开始45分钟后给予小剂量（5克）葡萄糖脉冲时，急性胰岛素反应与输注前脉冲相比明显减弱，而对15单位促胰液素脉冲的急性胰岛素反应（2 - 5分钟免疫反应性胰岛素变化量，微单位/毫升）增加了两倍多（之前：31.1±15.4；期间：71.2±40.4，微单位/毫升，平均值±标准差，P < 0.02）。在持续葡萄糖输注20小时后也发现对促胰液素的反应增加，但在输注停止1小时后，当血浆葡萄糖水平恢复到对照值时未观察到这种情况。因此，这种对促胰液素的反应增加是依赖葡萄糖的。每隔30分钟给予四个15 units促胰液素脉冲，随着后续每个脉冲，急性胰岛素反应逐渐且显著减弱，这与小储存池的耗竭一致。与促胰液素胰岛素反应幅度依赖葡萄糖的观察结果相似，葡萄糖刺激的输出似乎也依赖促胰液素。因此，促胰液素预处理后对5克葡萄糖的急性胰岛素反应增加（促胰液素预处理前：34.9±14.8；促胰液素预处理后：50.5±22.5微单位/毫升，P < 0.02），这表明促胰液素可能会扩大由葡萄糖刺激的储存池或增加其敏感性。肾上腺素和普萘洛尔对促胰液素和葡萄糖急性胰岛素反应的影响也不同。15单位促胰液素脉冲不受肾上腺素输注（之前：31.6±17.9；期间：27.8±16.6微单位/毫升）或普萘洛尔输注（之前：12.8±8.4；期间：10.7±5.5微单位/毫升）的影响。这些研究结果表明，虽然葡萄糖和促胰液素都能刺激快速的胰岛素反应，但这些反应很容易区分。数据表明，葡萄糖和促胰液素刺激功能上独立的胰岛素储存池，但对任何一种刺激的急性反应部分取决于对另一种刺激的暴露情况。
